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  • 1.
    Arrigan, Damien
    et al.
    NMRC, University College, Cork, Ireland.
    Ghita, Mihaela
    University of Salford, UK.
    Beni, Valerio
    NMRC, University College, Cork, Ireland.
    Selective voltammetric detection of dopamine in the presence ofascorbate2004In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 6, p. 732-733Article in journal (Refereed)
    Abstract [en]

    The selective detection of dopamine in the presence of ascorbateis demonstrated based on the voltammetry of dopamine transferacross the interface between two immiscible electrolyte solutions(ITIES) facilitated by an organic-phase ionophore; ascorbatetransfer does not occur, leading to highly selectivedetection of dopamine in the presence of excess ascorbate.

  • 2.
    Azzouzi, Sawsen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of sousse, Tunisia.
    Kor, Kalamodin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Damghan University, Iran.
    Ben Ali, Mounir
    University of sousse, Tunisia.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    A single probe based impedimetric biosensor for the label free, real time monitoring of microRNA-21 biomarker2016In: Biosensors 2016 – The World Congress on Biosensors, Gothenburg, Sweden, 25-27 May 2016, Elsevier, 2016Conference paper (Other academic)
  • 3.
    Azzouzi, Sawsen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of Sousse, Tunisia.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Kor, Kamalodin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Iranian National Institute Oceanog and Atmospher Science, Iran.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Ben Ali, Mounir
    University of Sousse, Higher Institute of Applied Sciences and Technology of Sousse, GREENS-ISSAT, Cité Ettafala, 4003 Ibn Khaldoun Sousse, Tunisia.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. ACREO SWEDISH ICE AB, Sweden.
    An integrated dual functional recognition/amplification bio-label for the one-step impedimetric detection of Micro-RNA-212017In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 92, p. 154-161Article in journal (Refereed)
    Abstract [en]

    Alteration in expression of miRNAs has been correlated with different cancer types, tumour stage and response to treatments. In this context, a structurally responsive oligonucleotide-based electrochemical impedimetric biosensor has been developed for the simple and sensitive detection of miRNA-21. A highly specific biotinylated DNA/LNA molecular beacon (MB) probe was conjugated with gold nanoparticles (AuNPs) to create an integrated, dual function bio-label (biotin-MB-AuNPs) for both biorecognition and signal generation. In the presence of target miRNA-21, hybridisation takes place resulting in the "activation" of the biotin-MB; this event makes the biotin group, which was previously "protected" by the steric hindrance of the MB stem-loop structure, accessible. The activated biotin-MB-AuNPs/miRNA complexes become available for capture, via supramolecular interaction, onto a nentravidin-modified electrode for electrochemical transduction. The binding event results in a decrease of the charge transfer resistance at the working electrode/electrolyte interface. The biosensor responded linearly in the range 1-1000 pM of miRNA-21, with a limit of detection of 0.3 pM, good reproducibility (Relative Standard deviation (RSD) =3.3%) and high selectivity over other miRNAs (i.e. miRNA221 and miRNA-205) sequences. Detection of miRNA-21 in spiked serum samples at clinically relevant levels (low pM range) was also demonstrated, thus illustrating the potential of the biosensor for point-of-care clinical applications. The proposed biosensor design, based on the combination of a neutravidin transducing surface and the dual-function biotin-MB-AuNPs bio-label, provides a simple and robust approach for detection of short-length nucleic acid targets, such as miRNAs.

    The full text will be freely available from 2019-02-10 10:23
  • 4.
    Bagheryan, Zahra
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of Mazandaran, Iran.
    Raoof, Jahan-Bakhsh
    University of Mazandaran, Iran.
    Golabi, Mohsen
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Acreo Swedish ICT AB, Sweden.
    Diazonium-based impedimetric aptasensor for the rapid label-free detection of Salmonella typhimurium in food sample2016In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 80, p. 566-573Article in journal (Refereed)
    Abstract [en]

    Fast and accurate detection of microorganisms is of key importance in clinical analysis and in food and water quality monitoring. Salmonella typhimurium is responsible for about a third of all cases of food borne diseases and consequently, its fast detection is of great importance for ensuring the safety of foodstuffs. We report the development of a label-free impedimetric aptamer-based biosensor for S. typhimurium detection. The aptamer biosensor was fabricated by grafting a diazonium-supporting layer onto screen printed carbon electrodes (SPEs), via electrochemical or chemical approaches, followed by chemical immobilisation of aminated-aptamer. FTIR-ATR, contact angle and electrochemical measurements were used to monitor the fabrication process. Results showed that electrochemical immobilisation of the diazonium-grafting layer allowed the formation of a denser aptamer layer, which resulted in higher sensitivity. The developed aptamer-biosensor responded linearly, on a logarithm scale, over the concentration range 1 x 10(1) to 1 x 10(8) CFU mL(-1), with a limit of quantification (LOQ) of 1 x 10(1) CFU mL(-1) and a limit of detection (LOD) of 6 CFU mL(-1). Selectivity studies showed that the aptamer biosensor could discriminate S. typhimurium from 6 other model bacteria strains. Finally, recovery studies demonstrated its suitability for the detection of S. typhimurium in spiked (1 x 10(2), 1 x 10(4) and 1 x 10(6) CFU mL(-1)) apple juice samples. (C) 2016 Elsevier B.V. All rights reserved.

  • 5.
    Bagheryan, Zahra
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of Mazandaran, Iran.
    Raoof, J-B
    University of Mazandaran, Iran.
    Ozalp, V.C.
    Istanbul Kemerburgaz University, Turkey.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Diazonium-based impedimetric aptasensor for the rapid label-free detection of Salmonella typhimurium in food samples2016In: Biosensors 2016 – The World Congress on Biosensors, Gothenburg, Sweden, 25-27 May 2016, Elsevier, 2016Conference paper (Other academic)
  • 6.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics.
    Biosensors for Food and the Environment: Is it all in the DNA?2013Conference paper (Other academic)
    Abstract [en]

    Biosensor technology not only holds great promise for the healthcare market but it is also expected to have significant impacts in other areas such as environmental and food analysis. Between the different biosensor formats nucleic acid-based biosensors are gaining increasingly importance allowing the specific identification of DNA/RNA fragments and, more recently, the detection of biological or chemical species. Direct identification of DNA/RNA fragments, via hybridisation assays (genosensors), has been shown to be a very powerful tool for the detection of pathogens in environment and food, in food contamination analysis and food allergens monitoring. Recently the discovery of aptamers, synthetic receptors based on short functional DNA/RNA chains, has opened new opportunities for oligonucleotide based biosensors and more specifically in the detection of biological and/or chemical species, such as proteins and pollutants. In this paper an overview of the most recent advances in the development and applications of nucleic acid-based biosensors for environmental and food safety/quality application will be presented with special emphasis on electrochemical and optical hybridisation genosensors and aptasensors.

  • 7.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Development of an electrochemical genosensors for celiac disease predisposition analysis2013In: "Biomimetic structures and DNA technology in biosensing" / [ed] Tibor Hianik, 2013, p. 21-Conference paper (Other academic)
    Abstract [en]

    Low density DNA arrays are of growing interest in the field of fast clinical/environmental analysis; for example in clinical analysis these can find application in areas as early diagnosis of genetic diseases or as support in the diagnosis of genetically associated diseases. 

    Coeliac disease, a small intestinal inflammation triggered by the intake of gluten, has been shown to affect only genetically predisposed individuals. Relation between Coeliac disease and two Human Leukocyte Antigens (HLA) genes, DQ2 and DQ8, has been reported, with almost 100% of the affected patients carrying at least one of them.

    In this seminar the development of a low density electrochemical genosensor array for medium resolution typing of Coeliac disease associated HLA genes, is presented.                                        

    The proposed array was based on an enzymatic sandwich assay format performed at a photolitographically fabricated electrode array.                                                                            

    The optimisation of different aspects as surface chemistry, assay conditions, probe's design and single stranded DNA generation, together with real sample analysis will be present.

     

  • 8.
    Beni, Valerio
    et al.
    Tyndall National Institute, University College Cork, Ireland.
    Arrigan, Damien
    Tyndall National Institute, University College Cork, Ireland.
    Microelectrode arrays and microfabricated devices in electrochemical stripping analysis2008In: Current Analytical Chemistry, ISSN 1573-4110, E-ISSN 1875-6727, Vol. 4, no 3, p. 229-241Article in journal (Refereed)
    Abstract [en]

    In this article a comprehensive overview of the developments in the field of electrochemical stripping analysis with microelectrode arrays and microfabricated devices is presented. Due to the vastness of the topic, this mini-review deals only with the use of regular microelectrode arrays. After the description of the main fabrication methodologies employed, a large part of the review is dedicated to applications, categorised by the electrode material. Microelectrode arrays have found application in several areas of electroanalytical science including clinical and environmental analysis. They have been used for the detection of heavy metals in waters, soil extracts and blood, proving to be reliable analytical devices and bringing the advantages of low-cost, simplicity of use and easy adaptability to field measurement. In many applications, limits of detection are sub-parts per billion. Finally a short section of the review discusses miniaturised potentiostats.

  • 9.
    Beni, Valerio
    et al.
    Tyndall National Institute, University College Cork, Ireland.
    Collins, Gilian
    Tyndall National Institute, University College Cork, Ireland.
    Arrigan, Damien
    Tyndall National Institute, University College Cork, Ireland.
    Investigation into the voltammetric behaviour and detection of selenium(IV) at metal electrodes in diverse electrolyte media2011In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 699, no 2, p. 127-133Article in journal (Refereed)
    Abstract [en]

    The voltammetric behaviour of selenium(IV) was studied at platinum and gold electrodes in sulphuricacid, perchloric acid and potassium chloride media as a basis for its voltammetric detection. The bestvoltammetric behaviour was recorded at gold electrodes with perchloric acid as the supporting electrolyte.The concomitant presence of metals, such as copper or lead, and of model biomolecules, suchas bovine serum albumin, in the solution resulted in a deterioration of the electrochemical response forselenium(IV). Quantitative detection of selenium(IV) by square wave anodic stripping voltammetry atboth a millimetre-sized gold disc electrode and a microband electrode array revealed linear responsesto selenium concentration in the ranges 5–15 M and 0.1–10 M, respectively, with 60 s preconcentration.The sensitivities were 6.4 A M−1 cm−2 and 100 A M−1 cm−2 at the disc and the microband array,respectively. The detection limit at the microband electrode array was 25 nM, illustrating the potentialityof such microelectrodes for the development of mercury-free analytical methods for the trace detectionof selenium(IV).

  • 10.
    Beni, Valerio
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Gelaw, Tilahun
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Study of the combination of the deposition/stripping of sacrificial metal nano-structures and alkanethiol as a route for genosensor surface preparation2011In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 13, no 4, p. 325-327Article in journal (Refereed)
    Abstract [en]

    In the reported work the combination of electrodeposition/stripping of copper sacrificial metallic nanostructuresand alkanethiol self-assembling was investigated for the preparation of a randomly nano-patternedorganised monolayer on a gold surface. Electrochemical characterisation of the process demonstrated thepotential of the proposed approach for the random nano-patterning of a chemisorbed monolayer onconductive surfaces with minimal impact on the bulk monolayer. Finally the obtained nano-structuredsurfaces were exploited as a platform for the fabrication of an amperometric genosensor for the detection ofthe DF508 Cystic Fibrosis associated mutation.

  • 11.
    Beni, Valerio
    et al.
    NMRC, University College, Cork, Ireland.
    Ghita, Mihaela
    PSiMedica, Malvern Hills Science Park, UK.
    Arrigan, Damien
    NMRC, University College, Cork, Ireland.
    Cyclic and pulse voltammetric study of dopamine at the interfacebetween two immiscible electrolyte solutions2005In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 20, no 10, p. 2097-2103Article in journal (Refereed)
    Abstract [en]

    The detection of dopamine by differential pulse voltammetry (DPV) and square wave voltammetry (SWV) at the interface between twoimmiscible electrolyte solutions (ITIES) has been studied. Voltammetry at the liquid/liquid (water/1,2-dichloroethane) interface provides asimple method for overcoming the major problem associated with dopamine detection by voltammetry at solid electrodes: the co-existenceof ascorbate at higher concentrations. Selectivity for dopamine was achieved by the use of dibenzo-18-crown-6 as an ionophore for thefacilitated transfer voltammetry of protonated dopamine across the ITIES. Under these conditions, ascorbate is not transferred and hence doesnot interfere in the ion transfer current for dopamine. By use of DPV and SWV, the lowest concentration detectable can be lowered from ca.0.1mM (obtained with cyclic voltammetry) to 2 M. Evaluation of the effect of some other physiologically important species (acetylcholine,sodium, potassium and ammonium ions) on the dopamine transfer voltammetry has been studied, indicating the need for improved ionophoredesigns in order to achieve practically useful selectivity.

  • 12.
    Beni, Valerio
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Hayes, Karen
    Universitat Rovira i Virgili, Tarragona, Spain.
    Mairal Lerga, Teresa
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Development of a gold nano-particle-based fluorescent molecular beacon fordetection of cystic fibrosis associated mutation2010In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 26, no 2, p. 307-313Article in journal (Refereed)
    Abstract [en]

    Cystic fibrosis is one of the most common genetically inherited diseases in Northern Europe, consistingof an inherited defect of chloride transport in the epithelium. Of the several mutations related to CF, theF508 mutation occurs in ca. 70% of the cases. In this work the use of a gold nano-particle supportedfluorescence molecular beacon was investigated as an optical sensing platform for the detection of theF508 cystic fibrosis associated mutation. Different parameters such as molecular beacon design, Aunano-particle size, molecular beacon–nano-particle conjugation protocol, molecular beacon loading aswell as experimental conditions were evaluated. A 31-base long molecular beacon, containing a 15-baserecognition sequence specific for the mutant target, was linked via a thiol modified poly thymine linker(10 bases long) to a 13 nm gold nano-particle and was exposed to mutant and wild type targets, and aclear differentiation was achieved at target concentrations as low as 1 nM.

  • 13.
    Beni, Valerio
    et al.
    NMRC, University College, Cork, Ireland.
    Newton, Hazel
    NMRC, University College, Cork, Ireland.
    Arrigan, Damien
    NMRC, University College, Cork, Ireland.
    Hill, Martin
    NMRC, University College, Cork, Ireland.
    Lane, William
    NMRC, University College, Cork, Ireland.
    Mathewson, Alan
    NMRC, University College, Cork, Ireland.
    Voltammetric behaviour at gold electrodes immersed in the BCR sequential extraction scheme media: Application of underpotential deposition–stripping voltammetry to determination of copper in soil extracts2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 502, no 2, p. 195-206Article in journal (Refereed)
    Abstract [en]

    The development of mercury-free electroanalytical systems for in-field analysis of pollutants requires a foundation on the electrochemicalbehaviour of the chosen electrode material in the target sample matrices. In this work, the behaviour of gold working electrodes in the mediaemployed in the BCR sequential extraction protocol, for the fractionation of metals in solid environmental matrices, is reported. All three ofthe BCR sequential extraction media are redox active, on the basis of acidity and oxygen content as well as the inherent reducing or oxidisingnature of some of the reagents employed: 0.11M acetic acid, 0.1M hydroxylammonium chloride (adjusted to pH 2) and 1M ammoniumacetate (adjusted to pH 2) with added trace hydrogen peroxide. The available potential ranges together with the demonstrated detection oftarget metals in these media are presented. Stripping voltammetry of copper or lead in the BCR extract media solutions reveal a multi-peakbehaviour due to the stripping of both bulk metal and underpotential metal deposits. A procedure based on underpotential deposition–strippingvoltammetry (UPD-SV) was evaluated for application to determination of copper in 0.11M acetic acid soil extracts. A preliminary screeningstep in which different deposition times are applied to the sample enables a deposition time commensurate with UPD-SV to be selected sothat no bulk deposition or stripping occurs thus simplifying the shape and features of the resulting voltammograms. Choice of the suitabledeposition time is then followed by standards addition calibration. The method was validated by the analysis of a number of BCR 0.11Macetic acid soil extracts. Good agreement was obtained been the UPD-SV method and atomic spectroscopic results.

  • 14.
    Beni, Valerio
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Nilsson, D.
    Acreo Swedish ICT AB, Sweden.
    Arven, P.
    Elect Engn J2 Holding AB, Sweden.
    Norberg, P.
    Acreo Swedish ICT AB, Sweden.
    Gustafsson, G.
    Acreo Swedish ICT AB, Sweden.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Printed Electrochemical Instruments for Biosensors2015In: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 4, no 10, p. S3001-S3005Article in journal (Refereed)
    Abstract [en]

    Mobile diagnostics for healthcare, food safety and environmental monitoring, demand a new generation of inexpensive sensing systems suitable for production in high volume. Herein we report on the development of a new disposable electrochemical instrument exploiting the latest advances in printed electronics and printed biosensors. The current system is manufactured under ambient conditions with all interconnections printed; electrochemical measurements and data elaboration are realized by the integration onto the platform of two chips: a MICROCHIP-PIC24F16KA101 and a Texas Instruments LMP91000. A PEDOT.PSS vertical electrochromic display (VECD) is also incorporated into the system to visualize the data. A printed Enfucell 3V manganese dioxide battery was used to deliver the required power. Finally, in order to demonstrate the utility of the system, screen-printed sensors for the detection of glucose were added and the performance of the overall system was evaluated.

  • 15.
    Beni, Valerio
    et al.
    Tyndall National Institute, University College, Cork, Ireland.
    Ogurtsov, Vladimir
    Tyndall National Institute, University College, Cork, Ireland.
    Bakunin, Nikolai
    Tyndall National Institute, University College, Cork, Ireland.
    Arrigan, Damien
    Tyndall National Institute, University College, Cork, Ireland.
    Hill, Martin
    Cork Institute of Technology, Bishopstown, Cork, Ireland.
    Development of a portable electroanalytical system for the stripping voltammetry of metals: Determination of copper in acetic acid soil extracts2005In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 552, no 1-2, p. 190-200Article in journal (Refereed)
    Abstract [en]

    The development, characterisation and evaluation of a prototype portable electrochemical trace metal analyser are presented. The instrumentis a battery-powered microcontroller-based potentiostat, which implements anodic stripping voltammetry (ASV) at suitable sensor electrodes.It is capable of operating away from the laboratory, in the absence of an external power source and is usable by low-skilled personnel. Thedistinguishing feature of the instrument is its custom software, which enables sample pre-screening, data processing and sample dilution andstandard additions calculations to be carried out. The instrument has been evaluated by application of a methodology for the detection ofcopper in acetic acid soil extracts, both in the laboratory and in the field. Underpotential deposition staircase anodic stripping voltammetry(UPD-SCASV) of the copper at gold disk electrodes was used as a test method. There was good agreement between the instrument resultsand those from laboratory-based reference analytical methods for analyses carried out both in the laboratory and in the field.

  • 16.
    Beni, Valerio
    et al.
    Tyndall National Institute, University College Cork, Ireland.
    Valsesia, Andrea
    Joint Research Centre, Ispra, Italy.
    Colpo, Pascal
    Joint Research Centre, Ispra, Italy.
    Bretagnol, Frederic
    Joint Research Centre, Ispra, Italy.
    Rossi, Francois
    Joint Research Centre, Ispra, Italy.
    Arrigan, Damien
    Tyndall National Institute, University College Cork, Ireland.
    Electrochemical properties of polymeric nanopatterned electrodes2007In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 9, no 7, p. 1833-1839Article in journal (Refereed)
    Abstract [en]

    An investigation of the electrochemical behaviour of gold electrodes coated with poly(ethylene glycol) (PEG), poly(acrylic acid)(PAA) and nanopatterned PAA/PEG layers is presented. Plasma-enhanced chemical vapour deposition and colloidal lithography wereused to produce nanodomes of PAA in a matrix of PEG. The electrochemical response at these nanostructured electrodes was studied asa function of the probe ion charge. Results show that the film structures allow the electrodes to retain their electrochemical activity whileminimising surface fouling and will thus be useful in the development of electrochemical nanobiosensors for various applications.

  • 17.
    Beni, Valerio
    et al.
    Universitat Rovira i Virgili, Spain.
    Zewdu, Taye
    Universitat Rovira i Virgili, Spain.
    Joda, Hamdi
    Universitat Rovira i Virgili, Spain.
    Katakis, Ioanis
    Universitat Rovira i Virgili, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Spain.
    Gold nanoparticle fluorescent molecular beacon for low-resolution DQ2 gene HLA typing2012In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 402, no 3, p. 1001-1009Article in journal (Refereed)
    Abstract [en]

    Coeliac disease is an inflammation of the small intestine triggered by gluten ingestion. We present a fluorescent genosensor, exploiting molecular-beacon-functionalized gold nanoparticles, for the identification of human leukocyte antigen (HLA) DQ2 gene, a key genetic factor in coeliac disease. Optimization of sensor performance was achieved by tuning the composition of the oligonucleotide monolayer immobilized on the gold nanoparticle and the molecular beacon design. Co-immobilization of the molecular beacon with a spacing oligonucleotide (thiolated ten-thymine oligonucleotide) in the presence of ten-adenine oligonucleotides resulted in a significant increase of the sensor response owing to improved spacing of the molecular beacons and extension of the distance from the nanoparticle surface, which renders them more available for recognition. Further increase in the response (approximately 40%) was shown to be achievable when the recognition sequence of the molecular beacon was incorporated in the stem. Improvement of the specificity of the molecular beacons was also achieved by the incorporation within their recognition sequence of a one-base mismatch. Finally, gold nanoparticles functionalized with two molecular beacons targeting the DQA1*05* and DQB1*02* alleles allowed the low-resolution typing of the DQ2 gene at the nanomolar level.

  • 18.
    Berduque, Alfonso
    et al.
    Tyndall National Institute, University College, Cork, Ireland.
    Lanyon, Yvonne
    Tyndall National Institute, University College, Cork, Ireland.
    Beni, Valerio
    Tyndall National Institute, University College, Cork, Ireland.
    Herzog, Gregoire
    Tyndall National Institute, University College, Cork, Ireland.
    Watson, Yvonne
    Tyndall National Institute, University College, Cork, Ireland.
    Rodgers, Kenneth
    Tyndall National Institute, University College, Cork, Ireland.
    Stam, Frank
    Tyndall National Institute, University College, Cork, Ireland.
    Alderman, John
    Tyndall National Institute, University College, Cork, Ireland.
    Arrigan, Damien
    Tyndall National Institute, University College, Cork, Ireland.
    Voltammetric characterisation of silicon-based microelectrode arrays and their application to mercury-free stripping voltammetry of copper ions2007In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 71, no 3, p. 1022-1030Article in journal (Refereed)
    Abstract [en]

    This paper describes the electrochemical characterisation of a range of gold and platinum microelectrode arrays (MEAs) fabricated by standardphotolithographic methods. The inter-electrode spacing, geometry, numbers and dimensions of the electrodes in the arrays were found to influencethe voltammetric behaviours obtained. Excellent correlation was found between experimental data and theoretical predictions employing publishedmodels of microelectrode behaviour. Gold MEAs were evaluated for their applicability to copper determination in a soil extract sample, whereagreement was found between the standard analytical method and a method based on underpotential deposition—anodic stripping voltammetry(UPD-ASV) at the MEAs, offering a mercury-free alternative for copper sensing.

  • 19.
    Debela, Ahmed M.
    et al.
    UPMC Univ Paris 06, France.
    Ortiz, Mayreli
    Univ Rovira and Virgili, Spain.
    Beni, Valerio
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. Res Inst Sweden, Sweden.
    Lesage, Denis
    UPMC Univ Paris 06, France.
    Cole, Richard
    UPMC Univ Paris 06, France.
    OSullivan, Ciara K.
    Univ Rovira and Virgili, Spain; Inst Catalana Recerca and Estudis Avancats, Spain.
    Thorimbert, Serge
    UPMC Univ Paris 06, France.
    Hasenknopf, Bernold
    UPMC Univ Paris 06, France.
    Functionalized Deoxynucleotides and DNA Primers for Electrochemical Diagnostics of Disease Predispostions2017In: SELECTED PROCEEDINGS FROM THE 231ST ECS MEETING, ELECTROCHEMICAL SOC INC , 2017, Vol. 77, no 11, p. 1873-1883Conference paper (Refereed)
    Abstract [en]

    Redox labeled DNAs are of increasing interest for the fabrication of next generation molecular tools. In the present work we are investigating the use of various redox labeled dNTPs, ddNTPs and DNA primers for use in detection of diseases. We have reported the use of Polyoxometalate (POM) labeled DNA primers and dNTPs for use in PCR and subsequently used for direct electrochemical detection of PCR products. The use of POM labeled DNAs in PCR enabled us to check the compatibility with polymerases and PCR incorporability of the modified DNAs. Furthermore we have investigated the solid-phase array based primer extension (e-PEX) with redox labelled ddNTPs (ferrocene (Fc), anthraquinone (AQ) phenothiazine (PTZ) and methylene blue (MB)) to prove the strategy of detection of single nucleotide polymorphisms using the labeled ddNTPs. This strategy will allow the development of cost-effective, rapid and user-friendly platform for the screening of known and unknown genetic mutations.

  • 20.
    Debela, Ahmed M.
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Ortiz, Mayreli
    Universitat Rovira i Virgili, Tarragona, Spain.
    Beni, Valerio
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain and ICREA, Barcelona, Spain.
    Facile Electrochemical Hydrogenation and Chlorination of Glassy Carbon to Produce Highly Reactive and Uniform Surfaces for Stable Anchoring of Thiolated Molecules2014In: Chemistry - A European Journal, ISSN 0947-6539, Vol. 20, no 25, p. 7646-7654Article in journal (Refereed)
    Abstract [en]

    Carbon is a highly adaptable family of materials and is one of the most chemically stable materials known, providing a remarkable platform for the development of tunable molecular interfaces. Herein, we report a two-step process for the electrochemical hydrogenation of glassy carbon followed by either chemical or electrochemical chlorination to provide a highly reactive surface for further functionalization. The carbon surface at each stage of the process is characterized by AFM, SEM, Raman, attenuated total reflectance (ATR) FTIR, X-ray photoelectron spectroscopy (XPS), and electroanalytical techniques. Electrochemical chlorination of hydrogen-terminated surfaces is achieved in just 5 min at room temperature with hydrochloric acid, and chemical chlorination is performed with phosphorus pentachloride at 50 °C over a three-hour period. A more controlled and uniform surface is obtained using the electrochemical approach, as chemical chlorination is observed to damage the glassy carbon surface. A ferrocene-labeled alkylthiol is used as a model system to demonstrate the genericity and potential application of the highly reactive chlorinated surface formed, and the methodology is optimized. This process is then applied to thiolated DNA, and the functionality of the immobilized DNA probe is demonstrated. XPS reveals the covalent bond formed to be a CS bond. The thermal stability of the thiolated molecules anchored on the glassy carbon is evaluated, and is found to be far superior to that on gold surfaces. This is the first report on the electrochemical hydrogenation and electrochemical chlorination of a glassy carbon surface, and this facile process can be applied to the highly stable functionalization of carbon surfaces with a plethora of diverse molecules, finding widespread applications.

  • 21. Felini, Usisipho
    et al.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Iwuoha, Emanuel
    University of the Western Cape, South Africa.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Palladium telluride quantum dots and cytochrome P450 biosensor for the detection of breast cancer drug – tamoxifen.2015In: Sweden-Japan Seminar on Nanomaterials and Nanotechnology – SJS-Nano, Linköping, Sweden, 10-11 March 2015., Japan Society for the Promotion of Science (JSPS), Stockholm. , 2015Conference paper (Refereed)
    Abstract [en]

    Tamoxifen is an oral non-steroidal anti-estrogen drug used in the prevention and treatment of all stages of breast cancer. This drug acts by competing with estrogen for binding to the estrogen receptor (ER) and reduces the transcription of estrogen dependent genes. However, approximately 30-50% of ER-positive breast cancer patients either fail to respond or eventually become resistant to tamoxifen resulting in a serious clinical challenge in breast cancer management. This, therefore, calls for new selective and sensitive methods for evaluating individual’s metabolic activities of the drug ensuring in this way reliable dosing of the drug. This paper presents a biosensor system based on the combination of thioglycolic acid-capped palladium telluride (TGA-PdTe) quantum dots (QDs) and cytochrome P450-3A4 or 2D6 (CYP3A4 or CYP2D6) enzymes for the determination of tamoxifen. Preliminary FTIR and UVs studies of the QDs confirmed the presence of the capping agent via the specific COOH and CH2 signature bands; furthermore the adsorption band at ca. 330 nm and the corresponding band gap energy, Eg, value is 3.47 eV (within the Eg value for QDs particles) confirmed the successful synthesis of the TGA-PdTe QDs. Differential pulse voltammetric (DPV) electroanalysis using the Au|Cyst|TGA-PdTeQDs|CYP3A4 (or CYP2D6) biosensor systems indicated a clear catalytic cathodic peak at -0.35 V for the tamoxifen biotransformation reaction; this signal was used, in this work, as the biosensor analytical response. The developed biosensor presented a limit of detection (LOD) of 0.98 and 2.5 ng/mL, for CYP3A4 and CYP2D6 based biosensors, respectively. These are lower than tamoxifen’s maximum steady state plasma concentration (Cmax 40 ng/L) value; these performances make the proposed biosensor a promising platform for monitoring the drug in patients.

  • 22. Golabi, Mohsen
    et al.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Kuralay, Feliz
    Uzun, Lokman
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Use of Phenylboronic Acid Derivatives in Molecular Imprinting of Whole Bacterial Cells2015In: 2nd International Congress on Biosensors – BiosensorTR2015, 10-12 June 2015, Izmir, Turkey., 2015Conference paper (Refereed)
    Abstract [en]

    The development of novel, rapid and inexpensive methods for the detection of bacteria will be beneficial in many fields including food and water safety, biosecurity, bioprocess control and clinical diagnostics. Of the possible alternatives, biosensors offer great potential to replace or complement traditional culture-based detection methods, which are time consuming, expensive and need equipped laboratories and trained staff.

     

    Molecularly-imprinted polymers (MIPs) are bio-inspired artificial receptors that are finding increasing use in biosensors. Unlike bio-receptors, they are more stable, inexpensive and easy to produce. Although imprinting of chemical and biological molecules has been very well studied, there is limited work on the imprinting of whole bacterial cells.  

    Bacterial cells are well-known to present several sugar compounds on their outer surface. In this paper, we explore the reversible interaction between boronic groups and diols for the development of highly specific MIPs for intact bacterial cells. 3-aminophenylboronic acid-based MIPs, for the detection of Staphylococcus epidermidis, were fabricated via chronoamperometric methods and   SEM images were used to verify the successful capturing and releasing of the whole bacterial cells. Successful capture and easy release of the bacterial cells, via a competitive approach, was demonstrated. Furthermore, the usefulness of this imprinting process for the specific detection of Staphylococcus epidermidis versus non-target bacteria, Staphylococcus aureus and Streptococcus pneumoniae, was also demonstrated by the use of impedance spectroscopy measurements of bacterial binding to MIPs and NIPs (non-imprinted polymers) electrodes.

  • 23.
    Golabi, Mohsen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Padiolleau, Laurence
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Cranfield University, England.
    Chen, Xi
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of Dundee, Scotland.
    Jafari, Mohammad Javad
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Sheikhzadeh, Elham
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Ferdowsi University of Mashhad, Iran.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Acreo Swedish ICT AB, Sweden.
    Doping Polypyrrole Films with 4-N-Pentylphenylboronic Acid to Enhance Affinity towards Bacteria and Dopamine2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 11, article id e0166548Article in journal (Refereed)
    Abstract [en]

    Here we demonstrate the use of a functional dopant as a fast and simple way to tune the chemical affinity and selectivity of polypyrrole films. More specifically, a boronic-functionalised dopant, 4-N-Pentylphenylboronic Acid (PBA), was used to provide to polypyrrole films with enhanced affinity towards diols. In order to prove the proposed concept, two model systems were explored: (i) the capture and the electrochemical detection of dopamine and (ii) the adhesion of bacteria onto surfaces. The chemisensor, based on overoxidised polypyrrole boronic doped film, was shown to have the ability to capture and retain dopamine, thus improving its detection; furthermore the chemisensor showed better sensitivity in comparison with overoxidised perchlorate doped films. The adhesion of bacteria, Deinococcus proteolyticus, Escherichia coli, Streptococcus pneumoniae and Klebsiella pneumoniae, onto the boric doped polypyrrole film was also tested. The presence of the boronic group in the polypyrrole film was shown to favour the adhesion of sugar-rich bacterial cells when compared with a control film (Dodecyl benzenesulfonate (DBS) doped film) with similar morphological and physical properties. The presented single step synthesis approach is simple and fast, does not require the development and synthesis of functional monomers, and can be easily expanded to the electrochemical, and possibly chemical, fabrication of novel functional surfaces and interfaces with inherent pre-defined sensing and chemical properties.

  • 24.
    Hatamie, Amir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Shahid Chamran University, Iran.
    Khan, Azam
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. NED University of Engn and Technology, Pakistan.
    Golabi, Mohsen
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Sadollah Khani, Azar
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Shahid Chamran University, Iran.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Zargar, Behrooz
    Shahid Chamran University, Iran.
    Bano, Sumaira
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Zinc Oxide Nanostructure-Modified Textile and Its Application to Biosensing, Photocatalysis, and as Antibacterial Material2015In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, no 39, p. 10913-10921Article in journal (Refereed)
    Abstract [en]

    Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photo catalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photo catalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles.

  • 25.
    Henry, Olivier
    et al.
    Universitat Rovira I Virgili, Tarragona, Spain.
    Fragoso, Alex
    Universitat Rovira I Virgili, Tarragona, Spain.
    Beni, Valerio
    Universitat Rovira I Virgili, Tarragona, Spain.
    Laboria, Noemi
    Universitat Rovira I Virgili, Tarragona, Spain.
    Acero Sanchez, Jose Luis
    Universitat Rovira I Virgili, Tarragona, Spain.
    Latta, Daniel
    Institut für Mikrotechnik Mainz GmbH, Mainz, Germany.
    Von Germar, Frithoj
    Institut für Mikrotechnik Mainz GmbH, Mainz, Germany.
    Drese, Klaus
    Institut für Mikrotechnik Mainz GmbH, Mainz, Germany.
    Katakis, Ioanis
    Universitat Rovira I Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira I Virgili, Tarragona, Spain.
    Design and testing of a packaged microfluidic cell for the multiplexed electrochemical detection of cancer markers2009In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 30, no 19, p. 3398-3405Article in journal (Refereed)
    Abstract [en]

    We present the rapid prototyping of electrochemical sensor arrays integrated to microfluidicstowards the fabrication of integrated microsystems prototypes for point-of-carediagnostics. Rapid prototyping of microfluidics was realised by high-precision milling ofpolycarbonate sheets, which offers flexibility and rapid turnover of the desired designs. Onthe other hand, the electrochemical sensor arrays were fabricated using standard photolithographicand metal (gold and silver) deposition technology in order to realise threeelectrodecells comprising gold counter and working electrodes as well as silver referenceelectrode. The integration of fluidic chips and electrode arrays was realised via a lasermachineddouble-sided adhesive gasket that allowed creating the microchannels necessaryfor sample and reagent delivery. We focused our attention on the reproducibility of theelectrode array preparation for the multiplexed detection of tumour markers such ascarcinoembryonic antigen and prostate-specific antigen as well as genetic breast cancermarkers such as estrogen receptor-a, plasminogen activator urokinase receptor, epidermalgrowth factor receptor and erythroblastic leukemia viral oncogene homolog 2. We showedthat by carefully controlling the electrode surface pre-treatment and derivatisation viathiolated antibodies or short DNA probes that the detection of several key health parameterson a single chip was achievable with excellent reproducibility and high sensitivity.

  • 26.
    Herzog, Gregoire
    et al.
    Université de Lorraine, France;CNRS, LCPME, France.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Stripping voltammetry at micro-interface arrays: A review2013In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 769, p. 10-21Article, review/survey (Refereed)
    Abstract [en]

    In this article, a comprehensive overview of the most recent developments in the field of stripping voltammetryat regular micro-interfaces (both solid–liquid and liquid–liquid interfaces) is presented. Thisreview will report on the most conventional arrays of metallic micro-electrodes but also on the rapidlygrowing field of electrochemistry at arrays of micro-interfaces between two immiscible electrolyte solutions(ITIES). The main fabrication methods, together with some design considerations and diffusionphenomena at such interfaces are discussed. Main applications of micro-interface arrays are presentedincluding heavy metals detection at micro-electrode arrays and detection of organic molecules (aminoacids, vitamins, peptides and drugs) at the ITIES. Stripping analysis at micro-interface arrays is suitablefor the detection of analytes in several real media including water, soil extracts and biological fluids(blood and saliva) with high specificity, sensitivity (detection limits of nM, ppb level) and reliability.Stripping analysis at ITIES and micro-electrode arrays are two complementary approaches that havethe advantages of being cost effective, simple to use and easily adaptable to field measurement.

  • 27.
    Herzog, Gregoire
    et al.
    NMRC, University College, Cork, Ireland.
    Beni, Valerio
    NMRC, University College, Cork, Ireland.
    Dillon, Patrick
    NMRC, University College, Cork, Ireland.
    Barry, Thomas
    NMRC, University College, Cork, Ireland.
    Arrigan, Damien
    NMRC, University College, Cork, Ireland.
    Effect of humic acid on the underpotential deposition-strippingvoltammetry of copper in acetic acid soil extract solutions atmercaptoacetic acid-modified gold electrodes2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 511, no 1, p. 137-143Article in journal (Refereed)
    Abstract [en]

    Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bareand modified gold electrodes in 0.11M acetic acid, the first fraction of the European Union’s Bureau Communautaire de Références (BCR)sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showedhigher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acidsolutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l−1 of humic acid, themercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayerformed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of thehumic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modifiedelectrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic resultsyielded the straight-line equation y (g l−1) = 1.10x − 44 (ppb) (R = 0.992, n = 6), indicating good agreement between the two methods.

  • 28.
    Ibupoto, Zafar Hussain
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Novel CuO Nanosheets and Their Non-Enzymatic Glucose Sensing Applications2013In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 13, no 6, p. 7926-7938Article in journal (Refereed)
    Abstract [en]

    Abstract: In this study, we have developed a sensitive and selective glucose sensor using novel CuO nanosheets which were grown on a gold coated glass substrate by a low temperature growth method. X-ray differaction (XRD) and scanning electron microscopy (SEM) techniques were used for the structural characterization of CuO nanostructures. CuO nanosheets are highly dense, uniform, and exhibited good crystalline array structure. X-ray photoelectron spectroscopy (XPS) technique was applied for the study of chemical composition of CuO nanosheets and the obtained information demonstrated pure phase CuO nanosheets. The novel CuO nanosheets were employed for the development of a sensitive and selective non-enzymatic glucose sensor. The measured sensitivity and a correlation coefficient are in order 5.20 × 102 µA/mMcm2 and 0.998, respectively. The proposed sensor is associated with several advantages such as low cost, simplicity, high stability, reproducibility and selectivity for the quick detection of glucose.

  • 29.
    Ibupoto, Zafar
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Non-Enzymatic Glucose Sensor Based on the Novel Flower Like Morphology of Nickel Oxide2013In: Soft Nanoscience Letters, ISSN 2160-0600, E-ISSN 2160-0740, Vol. 3, p. 46-50Article in journal (Refereed)
    Abstract [en]

    In this study, novel nickel oxide (NiO) flowers like nanostructures were fabricated onto gold coated glass substrate by hydrothermal method using high alkaline pH medium. The structural study of nickel oxide nanostructures was per-formed by scanning electron microscopy (SEM) and X-ray differaction (XRD) techniques. Nickel oxide nanostructures are highly dense, uniform and possess good crystalline quality. The so prepared structures were investigated for their electrochemical properties by cyclic voltammetry and amperometric techniques. The nickel oxide flower like morphol-ogy has shown good electrochemical performances for the oxidation of glucose. The presented sensing material was able to detected glucose in a wide range of concentration of 0.001 mM to 8 mM with a high sensitivity (123 μmA/mM) and regression coefficient of 0.99. Moreover, the NiO nanostructures based sensor is highly reproducible, stable, exhib-iting a fast response time and selective in the response. All the obtained results indicate the potential use of this material in the development of enzyme free sensors for the detection of glucose.

  • 30.
    Joda, Hamdi
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain .
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology. Universitat Rovira i Virgili, Tarragona, Spain .
    Alakkulpi, Noora
    Finnish Red Cross Blood Service, Helsinki, Finland .
    Partanen, Jukka
    Finnish Red Cross Blood Service, Helsinki, Finland .
    Lind, Kristina
    TATAA Biocenter AB, Göteborg, Sweden .
    Strömbom, Linda
    TATAA Biocenter AB, Göteborg, Sweden .
    Latta, Daniel
    Institut für Mikrotechnik Mainz GmbH, Germany.
    Höth, Julian
    Institut für Mikrotechnik Mainz GmbH, Germany .
    Katakis, Ioanis
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain; Institucio Catalana de Recerca i Estudis Avançats, Barcelona, Spain .
    Medium-high resolution electrochemical genotyping of HLA-DQ2/DQ8 for detection of predisposition to coeliac disease2014In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 406, no 12, p. 2757-2769Article in journal (Refereed)
    Abstract [en]

    Coeliac disease is a small intestinal disorder, induced by ingestion of gluten in genetically predisposed individuals. Coeliac disease has been strongly linked to human leukocyte antigens (HLA) located on chromosome 6, with almost 100 % of coeliac disease sufferers carrying either a HLA-DQ2 or HLA-DQ8 heterodimer, with the majority carrying HLA-DQ2 encoded by the DQA1*05:01/05:05, DQB1*02:01/02:02 alleles, whereas the remaining carry the HLA-DQ8 encoded by the DQA1*03:01, DQB1*03:02 alleles. In this work, we present the development of a multiplex electrochemical genosensor array of 36 electrodes, housed within a dedicated microfluidic platform and using a total of 10 sequence-specific probes for rapid medium-high resolution HLA-DQ2/DQ8 genotyping. An evaluation of the selectivity of the designed probes was carried out with the target sequences and 44 potentially interfering alleles, including single base mismatch differentiations; good selectivity was demonstrated. The performance of the electrochemical genosensor array was validated, analyzing real human samples for the presence of HLA-DQ2/DQ8 alleles, and compared with those obtained using laboratory-based HLA typing, and an excellent correlation was obtained.

  • 31.
    Joda, Hamdi
    et al.
    Universitat Rovira i Virgili, Spain.
    Beni, Valerio
    Universitat Rovira i Virgili, Spain.
    Curnane, Deidre
    Universitat Rovira i Virgili, Spain.
    Katakis, Ioanis
    Alakulppi, Noora
    Finnish Red Cross Blood Serv, Finland.
    Partanen, Jukka
    Finnish Red Cross Blood Serv, Finland.
    Lind, Kristina
    TATAA Bioctr AB, Sweden.
    Strombom, Linda
    TATAA Bioctr AB, Sweden.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Spain.
    Low-medium resolution HLA-DQ2/DQ8 typing for coeliac disease predisposition analysis by colorimetric assay2012In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 403, no 3, p. 807-819Article in journal (Refereed)
    Abstract [en]

    Coeliac disease is an inflammation of the small intestine, occurring in genetically susceptible individuals triggered by the ingestion of gluten. Human Leukocyte Antigens (HLA) DQ2 and DQ8 gene have been identified as key genetic factors in coeliac disease as they are presented in almost 100 % of the patients. These genes are encoded by the combination of certain alleles in the DQA and DQB region of chromosome 6. Specifically, DQA1*05:01 and DQB1*02:01 alleles for serologically defined leukocyte antigen DQ2 cis, DQA1*05:05 and DQB1*02:02 for DQ2 trans and DQA1*03:01 and DQB1*03:02 alleles for the DQ8. Specific identification of these alleles is a challenge due to the high number of alleles that have been identified so far: 46 in the DQA region and 160 in the DQB region (as of IMGT/HLA Database 10/2011 release). In the reported work, the development of a multiplex colorimetric assay for the low to medium HLA typing of the DQ2 and DQ8 genes is presented. The optimisation of probe design and assay conditions, performed by both surface plasmon resonance and enzyme-linked oligonucleotide assay, are reported. Finally, the performances of the developed typing platform were validated by the analysis of real patient samples and HLA typing, compared with those obtained using hospital based typing technology and an excellent correlation obtained.

  • 32.
    Joda, Hamdi
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Beni, Valerio
    INTERFIBIO Research Group, Departament d’Enginyeria Quimica, Universitat Rovira i Virgili, Tarragona, Spain.
    Katakis, Ioanis
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    DNA biosensor based on hybridization refractory mutation system approach for single mismatch detection2015In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 474, p. 66-68Article in journal (Refereed)
    Abstract [en]

    We report on a simple approach to enhance solid-phase hybridization-based single base mismatch discrimination at high ionic strength based on the deliberate insertion of a natural DNA base mismatch in the surface-tethered probe. A large drop in hybridization signal of single base mismatched alleles using the designed probe as compared with the conventional probe, from 80% to less than 25% of the signal obtained with the fully complementary, non-mutation-containing sequence, when using colorimetric detection was further improved to 20% when using electrochemical detection, attributable to a difference of spacing of immobilized probes. Finally, the designed probe was used for the electrochemical detection of the DQA1*05:05 allele amplified from real human blood samples.

  • 33.
    Khun, Kimleang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Z. H.
    University of Sindh Jamshoro, Pakistan.
    Liu, X.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The ethylene glycol template assisted hydrothermal synthesis of Co3O4 nanowires; structural characterization and their application as glucose non-enzymatic sensor2015In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 194, p. 94-100Article in journal (Refereed)
    Abstract [en]

    In the work reported herein the ethylene glycol template assisted hydrothermal synthesis, onto Au substrate, of thin and highly dense cobalt oxide (Co3O4) nanowires and their characterization and their application for non-enzymatic glucose sensing are reported. The structure and composition of Co3O4 nanowires have been fully characterized using scanning electron microscopy, X-ray diffraction, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The synthesized Co3O4 nanowires resulted to have high purity and showed diameter of approximately 10 nm. The prepared Co3O4 nanowires coated gold electrodes were applied to the non-enzymatic detection of glucose. The developed sensor showed high sensitivity (4.58 x 10(1) mu A mM(-1) cm(-2)), a wide linear range of concentration (1.00 x 10(-4)-1.2 x 10(1) mM) and a detection limit of 2.65 x 10(-5) mM. The developed glucose sensor has also shown to be very stable and selective over interferents such as uric acid and ascorbic acid. Furthermore, the proposed fabrication process was shown to be highly reproducible response (over nine electrodes).

  • 34.
    Khun, Kimleang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Mansor, N. A.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    An Electrochemical Dopamine Sensor Based on the ZnO/CuO Nanohybrid Structures2014In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 14, no 9, p. 6646-6652Article in journal (Refereed)
    Abstract [en]

    The selective detection of dopamine (DA) is of great importance in the modern medicine because dopamine is one of the main regulators in human behaviour. In this study, ZnO/CuO nanohybrid structures, grown on the gold coated glass substrate, have been investigated as a novel electrode material for the electrochemical detection of dopamine. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used for the material characterization and the obtained results are in good agreement. The selective determination of dopamine was demonstrated by cyclic voltammetry (CV) and amperometric experiments. The amperometric response was linear for dopamine concentrations between 1.0 x 10(-3) and 8.0 mM with a sensitivity of 90.9 mu A mM(-1) cm(-2). The proposed dopamine biosensor is very stable, selective over common interferents as glucose, uric acid and ascorbic acid, and also good reproducibility was observed for seven electrodes. Moreover, the dopamine sensor exhibited a fast response time of less than 10 s. The wide range and acceptable sensitivity of the presented dopamine sensor provide the possible application in analysing the dopamine from the real samples.

  • 35. Kor, Kamalodin
    et al.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Zarei, K
    Atabati, M
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mak, Martin
    Combining structure responsive probes and lateral-flow test; a simple and rapid approach miRNA-21 detection2015In: 2nd International Congress on Biosensors – BiosensorTR2015, 10-12 June 2015, Izmir, Turkey., 2015Conference paper (Refereed)
  • 36.
    Kor, Kamalodin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Zarei, Kobra
    School of Chemistry, Damghan University, Damghan, Iran.
    Atabati, Morteza
    School of Chemistry, Damghan University, Damghan, Iran.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Structurally responsive oligonucleotide-based single-probe lateral-flow test for detection of miRNA-21 mimics2016In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 408, no 5, p. 1475-1485Article in journal (Refereed)
    Abstract [en]

    A single-probe strip test for the rapid and sensitive detection of miRNA-21 mimics is reported herein. Highly specific structurally responsive bi-functional, thiol and biotin, DNA/LNA oligonucleotide probes (molecular beacons-MB) were designed and conjugated with gold nanoparticles (AuNPs) (i.e. biotin-MB-AuNPs). The proposed design had the ability to modulate the accessibility of the biotin group as a function of the presence of a miRNA target allowing the interaction of the boilable with the streptavidin test zone only in the presence of the miRNA-21 mimics. For quantitative evaluation, images of the strip tests were recorded using a flatbed scanner (Epson Perfection V370 Photo). The colour intensities of the test zones of the strip tests were analysed with the ImageJ software (Scion Corp., USA) and quantified as a function of pixel intensity. The response of the strip test was linear over the range 0.5 to 20 nM miRNA-21 (limit of detection of 115 pM) and showed good reproducibility (intra and inter CVs below 8 %); furthermore, the assay was shown to be highly selective, discriminating other interference miRNAs mimics (e.g. miRNA-221 and miRNA-205). Finally, the proposed strip test was used for detection of miRNA-21 mimics in spiked serum samples, demonstrating its potential for point-of-care clinical applications. Main advantages of the single-probe strip test design are its versatility, simplicity and robustness, which can be easily extended to other miRNA targets by tuning the sequence of the single probe. Furthermore, the use of the structurally responsive single probe is particularly relevant in the case of short-length targets, such as miRNA, whereas a conventional sandwich approach might require a careful control of assay conditions such as hybridization temperature and salt concentration

  • 37.
    Mak, Wing Cheung
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Lateral-flow technology: from visual to instrumental.2016In: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 79, no SI, p. 297-305Article in journal (Refereed)
    Abstract [en]

    Lateral-flow tests were first launched commercially in 1984, as a simple urine-based pregnancy test for home use. The simplicity of the visual readout delivered by the basic lateral-flow format proved to be a very popular. However, the recent apparently unstoppable trend towards portable and wearable technology is driving the lateral-flow strip towards an industrial interface that will enable it to interface with big data and expert systems, and where ready transmission of data is essential. In this review, we chart the inevitable evolution of the visually-read lateral-flow strip to more advanced instrumented versions and consider the future of this very flexible approach to delivering simple affinity assays. We examine recent labelling strategies, the relative merits of optical and electrochemical transducers and explore the evolution of recognition elements that are now being incorporated into these systems.

  • 38.
    Mansor, Nur Azimah
    et al.
    Universiti Teknologi MARA, Shah Alam, Malaysia.
    Zain, Zainiharyati Mohd
    Universiti Teknologi MARA, Shah Alam, Malaysia.
    Hamzah, Hairul Hisham
    Universiti Teknologi MARA, Shah Alam, Malaysia.
    Noorden, Mohd Shihabuddin Ahmad
    Universiti Teknologi MARA, Puncak Alam, Malaysia.
    Jaapar, Siti Safura
    Universiti Teknologi MARA, Puncak Alam, Malaysia.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Husain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Detection of Breast Cancer 1 (BRCA1) Gene Using an Electrochemical DNA Biosensor Based on Immobilized ZnO Nanowires2014In: Open Journal of Applied Biosensor, ISSN 2168-5401, Vol. 3, no 2, p. 9-17Article in journal (Refereed)
    Abstract [en]

    Herein we report an electrochemical DNA biosensor for the rapid detection of sequence (5’ AAT GGA TTT ATC TGC TCT TCG 3’) specific for the breast cancer 1 (BRCA1) gene. The proposed electrochemical genosensor is based on short oligonucleotide DNA probe immobilized onto zinc oxide nanowires (ZnONWs) chemically synthesized onto gold electrode via hydrothermal technique. The morphology studies of the ZnONWs, performed by field emission scanning electron microscopy (FESEM), showed that the ZnO nanowires are uniform, highly dense and oriented perpendicularly to the substrate. Recognition event between the DNA probe and the target was investigated by differential pulse voltammetry (DPV) in 0.1 M acetate buffer solution (ABS), pH 7.00; as a result of the hybridization, an oxidation signal was observed at +0.8 V. The influences of pH, target concentration, and non-complimentary DNA on biosensor performance were examined. The proposed DNA biosensor has the ability to detect the target sequence in the range of concentration between 10.0 and 100.0 µM with a detection limit of 3.32 µM. The experimental results demonstrated that the prepared ZnONWs/Au electrodes are suitable platform for the immobilization of DNA.

  • 39.
    Mehdi Debela, Ahmed
    et al.
    Universitat Rovira i Virgili.
    Ortiz, Mayreli
    Universitat Rovira i Virgili.
    Beni, Valerio
    Departament d'Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans, 26, 43007 Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili.
    Surface functionalisation of carbon for low cost fabrication of highly stable electrochemical DNA sensors2015In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 71, p. 25-29Article in journal (Refereed)
    Abstract [en]

    An alternative strategy for surface tethering of DNA probes, where highly reactive glassy carbon (GC) substrates are prepared via electrochemical hydrogenation and electrochemical/chemical chlorination is reported. Thiolated DNA probes and alkanethiols were stably immobilised on the halogenated carbon, with electrochemical chlorination being milder, thus producing less damage to the surface. Electrochemical DNA sensors prepared using this surface  chemistry on carbon with electrochemical chlorination providing an improved performance,producing a highly ordered surface and the use of lateral spacers to improve steric  accessibility to immobilised probes was not required.

  • 40.
    Nasef, Hany
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Beni, Valerio
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Electrochemical molecular beacon DNA biosensor for the detection and discrimination of the DF508 cystic fibrosis mutation2011In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 662, no 2, p. 322-327Article in journal (Refereed)
    Abstract [en]

    Cystic fibrosis is one of the most common genetically inherited diseases in Northern Europe, consisting of a defect of chloride transport in the epithelium, with the DF508 mutation being the most common mutation associated with the disease. In this work the design and characterisation of a reagent-less electrochemical genosensor, based on the use of an electrochemical molecular beacon targeting the DF508 mutation is presented. Different aspects of the sensing platform including molecular beacon design and surface chemistry of the sensor surface were evaluated. Operational parameters such as assay buffer and assay time were also optimised. Using the optimised molecular beacon designs a clear differentiation between the targeted sequence (i.e. mutant) and potential interferent (i.e. wild type) was demonstrated, with a total required assay time of 20 min. The major advantage of the proposed reagent-less sensing platform is the fact that this only required, as intervention of the end-user, the addition of the sample.

  • 41.
    Nasef, Hany
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain .
    Beni, Valerio
    Universitat Rovira i Virgili, Tarragona, Spain .
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain .
    Labelless electrochemical melting curve analysis for rapid mutation detection2010In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 2, no 10, p. 1461-1466Article in journal (Refereed)
    Abstract [en]

    In the post-genome era there is an increasing demand for cost effective and rapid methods for thedetection of specific mutations and single nucleotide polymorphisms. Here we describe a method forthe rapid detection of mutations exploiting labelless electrochemical melting curve analysis, using thedetection of the cystic fibrosis associated DF508 mutant as a model. A 21-base long thiolated probe,complementary to the region of Exon 10 of the cystic fibrosis transmembrane regulatory gene where theDF508 mutation lies, was immobilised on a gold electrode and hybridised to a synthetic analogue ofsingle stranded PCR products for each of the mutant (85 bases) and wild type (82 bases) targets.Experimental conditions were optimised to exploit the guanine-specific interaction of the electroactiveindicator, methylene blue. Upon hybridisation of the immobilised probe to the target, the number ofguanine bases present in close proximity with the sensor surface increased from 3 to 14, resulting ina significant increase in signal. Ramping of the temperature caused denaturation of the on-surfaceimmobilised duplex and a concomitant reduction in signal. From the first derivative of the meltingcurves a clear differentiation between the mutant and wild-type target could be observed. The proposedapproach can be extended to array based melting curve analysis, allowing the simultaneous detection ofmultiple mutations and SNPs, and moreover the melting properties observed can also be used to designgenosensors for single target detection.

  • 42.
    Nasef, Hany
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain .
    Beni, Valerio
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Methylene blue as an electrochemical indicator for DF508 cystic fibrosis mutation detection2010In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 396, no 4, p. 1423-1432Article in journal (Refereed)
    Abstract [en]

    Cystic fibrosis is one of the most common lifeshortening,childhood-onset inherited diseases. Among the1,000 known cystic fibrosis-related mutations, DF508 is themost common, with a frequency varying between 50% and70% according to geographical areas and populationtypology. In this work, we report the use of methyleneblue as an electrochemical reporting agent in the discriminationof synthetic PCR analogue of the DF508 cysticfibrosis mutation (Mut) from the wild type (Wt). Atoptimum experimental condition, a discrimination factorbetween mutant and wild type of approximately 1.5-foldwas found. The proposed assay was quantitative and linearin the range of 10–100 nM, exhibiting a limit of detectionof 2.64 nM. Electrochemical studies at variable ionicstrength conditions allowed further elucidation of themechanism of the methylene blue (MB)–DNA interaction.To the best of our knowledge, this is the first report ofdetection of hybridisation solely via guanine-specific MB–DNA interaction simultaneously in MB solution, independentof electrostatic interaction as demonstrated in the ionicstrength study. The introduction of formamide in thehybridization buffer, to improve discrimination, was alsoinvestigated. Finally, mutant wild type discrimination wasdemonstrated, at 10 nM concentration, with the use of amulti-sensor setup.

  • 43.
    Nasef, Hany
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Beni, Valerio
    Universitat Rovira i Virgili, Tarragona, Spain.
    Ozalp, Cengiz
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Cystic fibrosis: a label-free detection approach based on thermally modulated electrochemical impedance spectroscopy2010In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 396, no 7, p. 2565-2574Article in journal (Refereed)
    Abstract [en]

    Cystic fibrosis is one of the most commongenetically inherited diseases in northern Europe, with theDF508 mutation being the most common, and among theCaucasian population being responsible for almost 70% ofcases. In this work, we report on the use of thermallymodulated electrochemical impedance spectroscopy for thediscrimination of the DF508 mutation from the wild-typesequence. DNA probes (15 and 21 bases long) wereimmobilised on the surface of gold electrodes and thevariation of the charge-transfer resistance was monitored asa function of hybridisation. Two sets of targets were used inthis work: synthetic 15-mer sequences and two singlestrandedsynthetic analogues of PCR products 82 (mutant)and 85 (wild type) bases long. Hybridisation with shorttargets resulted in very sequence specific charge-transferresistancevariation with a discrimination factor at roomtemperature between fully complementary and mismatchedsequences of approximately fivefold. However, in the caseof the single-stranded synthetic PCR product analogues, alower discrimination factor was recorded (1.5-fold). Theeffect of temperature was investigated to improve discriminationand the use of a posthybridisation wash at elevatedtemperature resulted in a fivefold improvement in thediscrimination factor. Using an electrode array with probesimmobilised against each of the mutant and wild-typesequences, we achieved an unequivocal detection of theDF508 mutation.

  • 44.
    Nasef, Hany
    et al.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Cengiz, Ozalp
    Universitat Rovira i Virgili, Tarragona, Spain.
    Beni, Valerio
    Universitat Rovira i Virgili, Tarragona, Spain.
    O´Sullivan, Ciara K.
    Universitat Rovira i Virgili, Tarragona, Spain.
    Melting temperature of surface-tethered DNA2010In: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 406, no 1, p. 34-40Article in journal (Refereed)
    Abstract [en]

    A method for the accurate determination of the melting temperature (Tm) of surface-immobilized DNAduplexes that exploits the fluorescence-quenching properties of gold is reported. A thiolated singlestrandedDNA probe is chemisorbed onto a gold surface and then hybridized to a fluorophore-labeledcomplementary sequence. On formation of the duplex, the fluorescence of the label is effectivelyquenched by the gold surface. As the temperature is increased and the duplex denatures, the fluorophorelabel moves away from the gold surface and the fluorescence signal is again observed. The increase influorescence is measured as the temperature is ramped, and using first-derivative plots, the Tm is determined.To demonstrate the approach, the Tm of the cystic fibrosis DF508 mutation was determined inthree different phases: in solution, in suspension immobilized on gold nanoparticles, and immobilizedon gold film-coated substrate. The technique was further applied to optimize conditions for differentiationbetween a surface-immobilized DF508 mutant probe and a mutant/wild-type target exploitingincreasing stringency in varying salt and formamide concentrations. The approach has application inoptimization of assay conditions for biosensors that use gold substrates as well as in melting curveanalysis.

  • 45.
    Nilsson, David
    et al.
    Acreo Swedish ICT, Sweden.
    Theuer, Lorenz
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Acreo Swedish ICT, Sweden.
    Beni, Valerio
    Acreo Swedish ICT, Sweden.
    Dyreklev, Peter
    Acreo Swedish ICT, Sweden.
    Norberg, Petronella
    Acreo Swedish ICT, Sweden.
    Arven, Patrik
    Elect Engn J2 Holding AB, Sweden.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Gustafsson, Göran
    Acreo Swedish ICT, Sweden.
    Combining electrochemical bio-sensing, hybrid printed electronics and wireless communication for enabling real-time and remote monitoring of lactate2016In: Biosensors 2016 – The World Congress on Biosensors, Gothenburg, Sweden, 25-27 May 2016, Elsevier, 2016Conference paper (Other academic)
  • 46.
    Ogurtsov, Vladimir
    et al.
    Tyndall National Institute, University College Cork, Ireland.
    Beni, Valerio
    Tyndall National Institute, University College Cork, Ireland.
    Strutwolf, Jörgen
    Tyndall National Institute, University College Cork, Ireland.
    Arrigan, Damien
    Tyndall National Institute, University College Cork, Ireland.
    Study of the Effects of Nonlinear Potential Sweeps on Voltammetry2009In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 21, no 1, p. 68-76Article in journal (Refereed)
    Abstract [en]

    Voltammetric methods use a constant sweep rate during the course of a scan. This paper reports a study of theinfluence of a nonconstant sweep rate on the voltammetric response. In this approach, either continuously increasingor continuously decreasing potential scan rates can be employed, unlike presently available methods which rely on aconstant sweep rate. The voltammetric response of potassium ferrocyanide at a glassy carbon electrode was used as amodel system to test the new method. The responses obtained using traditional staircase voltammetry (linear staircasevoltammetry) and the new approach (nonlinear staircase voltammetry) were compared by experiment and bysimulation. The new approach offers capability for signal enhancement, whereby enhanced current or enhanced peakshape can be obtained by choice of appropriate waveform parameters.

  • 47.
    O'Mahony, Aoife
    et al.
    Tyndall National Institute, University College Cork, Ireland.
    Scanlon, Michael
    Tyndall National Institute, University College Cork, Ireland.
    Berduque, Alfonso
    Tyndall National Institute, University College Cork, Ireland.
    Beni, Valerio
    Tyndall National Institute, University College Cork, Ireland.
    Arrigan, Damien
    Tyndall National Institute, University College Cork, Ireland.
    Faggi, Enrico
    Università di Firenze, Italy.
    Bencini, Andrea
    Università di Firenze, Italy.
    Voltammetry of chromium(VI) at the liquid|liquid interface2005In: Electrochemistry communications, ISSN 1388-2481, E-ISSN 1873-1902, Vol. 7, no 10, p. 976-982Article in journal (Refereed)
    Abstract [en]

    The voltammetry of hexavalent chromium (ammonium dichromate) at the interface between two immiscible electrolyte solutionsis reported. Detection of Cr(VI) by ion transfer voltammetry is possible by use of an organic phase ionophore, which facilitates thetransfer of Cr(VI) from the aqueous into the organic phase. The ionophore was the penta protonated form of polyamine macrocycle2,5,8,11,14-pentaaza[15]-16,29-phenanthrolinophane (NeoTT). Cyclic voltammetry showed an increase of the peak current onincreasing the concentration of Cr(VI). Square wave voltammetry with background subtraction was employed for low level concentrationdetection. The lowest concentration detected was 0.25 parts per million of Cr(VI).

  • 48.
    Sekretaryova, Alina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    Karyakin, Arkady A.
    Moscow MV Lomonosov State University, Russia.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Vagin, Mikhail
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    Cholesterol Self-Powered Biosensor2014In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 86, no 19, p. 9540-9547Article in journal (Refereed)
    Abstract [en]

    Monitoring the cholesterol level is of great importance, especially for people with high risk of developing heart disease. Here we report on reagentless cholesterol detection in human plasma with a novel single-enzyme, membrane-free, self-powered biosensor, in which both cathodic and anodic bioelectrocatalytic reactions are powered by the same substrate. Cholesterol oxidase was immobilized in a sol-gel matrix on both the cathode and the anode. Hydrogen peroxide, a product of the enzymatic conversion of cholesterol, was electrocatalytically reduced, by the use of Prussian blue, at the cathode. In parallel, cholesterol oxidation catalyzed by mediated cholesterol oxidase occurred at the anode. The analytical performance was assessed for both electrode systems separately. The combination of the two electrodes, formed on high surface-area carbon cloth electrodes, resulted in a self-powered biosensor with enhanced sensitivity (26.0 mA M-1 cm(-2)), compared to either of the two individual electrodes, and a dynamic range up to 4.1 mM cholesterol. Reagentless cholesterol detection with both electrochemical systems and with the self-powered biosensor was performed and the results were compared with the standard method of colorimetric cholesterol quantification.

  • 49.
    Sekretaryova, Alina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Vagin, Mikhail Y
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    A highly sensitive and self-powered cholesterol biosensor2014In: 24th Anniversary World Congress on Biosensors – Biosensors 2014, Elsevier, 2014Conference paper (Other academic)
    Abstract [en]

    Blood cholesterol is a very important parameter for the assessment of atherosclerosis and other lipid disorders. The total cholesterol concentration in human blood should be less than 5.17 mM. Concentrations in the range 5.17 – 6.18 mM are considered borderline high risk and levels above 6.21 mM, high risk. Cholesterol determination with high accuracy is therefore necessary in order to differentiate these levels for medical screening or diagnosis. Several attempts to develop highly sensitive cholesterol biosensors have been described, but, to the best of our knowledge, this is the first report of a self-powered cholesterol biosensor, i.e. a device delivering the analytical information from the current output of the energy of the biocatalytic conversion of cholesterol, without any external power source. This is particularly relevant to the development of inexpensive screening devices based on printed electronics.

     

    We present two complementary bioelectrocatalytic platforms suitable for the fabrication of a self-powered biosensor. Both are based on cholesterol oxidase (ChOx) immobilisation in a sol-gel matrix, as illustrated in Fig. 1 [1]. Mediated biocatalytic cholesterol oxidation [2] was used as the anodic reaction and electrocatalytic reduction of hydrogen peroxide on Prussian Blue (PB) as the cathodic reaction. Due to a synergistic effect in the self-powered cholesterol biosensor, the analytical parameters of the overall device exceeded those of the individual component half-cells, yielding a sensitivity of 0.19 A M-1 cm-2 and a dynamic range that embraces the free cholesterol concentrations found in human blood.

     

    Thus, we have demonstrated the novel concept of highly sensitive cholesterol determination using the first self-powered cholesterol biosensor. This configuration is particularly promising for incorporation in emerging plastic- and paper-based analytical instruments for decentralised diagnostics and mobile health.

     

  • 50.
    Sekretaryova, Alina N
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    Karyakin, Arkady A
    Moscow State University, Russia.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Vagin, Mikhail Y
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, The Institute of Technology.
    Novel single-enzyme based self-powered biosensor2014In: 15th International Conference on Electroanalysis (ESEAC), 2014Conference paper (Other academic)
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