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  • 151.
    NEWMAN, JD
    et al.
    CRANFIELD UNIV,CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    TURNER, APF
    Cranfield University, UK.
    BIOSENSORS - THE ANALYSTS DREAM1994In: Chemistry and industry, ISSN 0009-3068, E-ISSN 2047-6329, no 10, p. 374-378Article in journal (Refereed)
    Abstract [en]

    n/a

  • 152.
    Newman, JD
    et al.
    Cranfield University, Silsoe MK45 4DT, Beds, England; .
    Turner, APF
    Cranfield University, UK.
    Home blood glucose biosensors: a commercial perspective2005In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 20, no 12, p. 2435-2453Article, review/survey (Refereed)
    Abstract [en]

    Twenty years on from a review in the first issue of this journal, this contribution revisits glucose sensing for diabetes with an emphasis on commercial developments in the home blood glucose testing market. Following a brief introduction to the needs of people with diabetes, the review considers defining technologies that have enabled the introduction of commercial products and then reviews the products themselves. Drawing heavily on the performance of actual instruments and publicly available information from the companies themselves, this work is designed to complement more conventional reviews based on papers published in scholarly journals. It focuses on the commercial reality today and the products that we are likely to see in the near future. (c) 2004 Elsevier B. V. All rights reserved.

  • 153.
    NEWMAN, JD
    et al.
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,CRANFIELD MK43 0AL,BEDS,ENGLAND; UNIV FLORENCE,DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALYT AMBIENTALE,I-50121 FLORENCE,ITALY; .
    TURNER, APF
    Cranfield University, UK.
    MARRAZZA, G
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,CRANFIELD MK43 0AL,BEDS,ENGLAND; UNIV FLORENCE,DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALYT AMBIENTALE,I-50121 FLORENCE,ITALY; .
    INK-JET PRINTING FOR THE FABRICATION OF AMPEROMETRIC GLUCOSE BIOSENSORS1992In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 262, no 1, p. 13-17Article in journal (Refereed)
    Abstract [en]

    Ink-jet printing has been demonstrated as a manufacturing technique that facilitates the rapid, reproducible and economical production of amperometric glucose biosensors. Glucose was chosen as the analyte for demonstrating the process. For eight electrodes produced, the relative standard deviation of the response was less than 5%. The technique is extremely versatile, and will enable a wide variety of reagents to be placed on virtually any sensor design. This technique will be of particular benefit for the mass manufacture of intricate devices, where existing production techniques, such as screen-printing, may not be suitable.

  • 154.
    Newman, JD
    et al.
    CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    White, SF
    CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    Tothill, IE
    CRANFIELD BIOTECHNOL CTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    Turner, APF
    Cranfield University, UK.
    An instrument for on-line monitoring of fermentations using FIA and amperometric biosensors. in ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, vol 213, issue , pp 59-BTEC1997In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC , 1997, Vol. 213, p. 59-BTECConference paper (Refereed)
    Abstract [en]

    n/a

  • 155.
    Newman, Jeffrey D.
    et al.
    Biotechnology Centre, Cranfield Institute of Technology, Bedford, U.K..
    Turner, Anthony P. F.
    Cranfield University, UK.
    Biosensors: principles and practice1992In: Essays in Biochemistry, ISSN 0071-1365, E-ISSN 1744-1358, Vol. 27, p. 147-159Article, review/survey (Refereed)
  • 156.
    Newman, Jeffrey D.
    et al.
    Cranfield university, UK.
    White, Stephen F.
    Cranfield university, UK.
    Tothill, Ibtisam E.
    Cranfield university, UK.
    Turner, Anthony P. F.
    Cranfield University, UK.
    Catalytic materials, membranes and fabrication technologies suitable for the construction of amperometric biosensors1995In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 67, no 24, p. 4594-4599Article in journal (Other academic)
    Abstract [en]

    A selection of recently available catalytic carbon powders were assessed and compared with the more conventionally used platinized material. Their suitability for incorporation in amperometric biosensors is discussed, In conjunction with this study, methods of applying membranes to the surfaces of these devices were investigated. Advanced fabrication technologies, potentially suitable for scale-up of sensor production, such as screen printing and ink-jet printing, were used for manufacture of the complete sensor structure. Hydrogen peroxide-sensing electrodes and glucose biosensors were produced as model systems, demonstrating the advantages of these approaches. The commercially available rhodinized carbon MCA4 produced a high current density at low potentials over a plateau region (300-400 mV vs SCE). In addition, direct oxidation of glucose (seen with platinized carbon) was not observed at the chosen potential of +350 mV. Further interference studies using fermentation media highlighted its suitability as an electrode material for use in complex samples. Ink-jet printing proved to be a successful method for the deposition of Nafion membranes of defined and reproducible geometry.

  • 157.
    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)
  • 158.
    Nordin, Anis
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Revuri, Vishnu
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Bhowmick, Neil
    Cedars-Sinai Medical Center, Los Angeles, USA.
    Voiculescu, Ioana
    City College of New York, USA.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Label-free Detection of Prostate Cancer Biomarker2014In: 24th Anniversary World Congress on Biosensors – Biosensors 2014 / [ed] Anthony Turner, Elsevier, 2014Conference paper (Other academic)
    Abstract [en]

    Prostate cancer is common and a frequent cause of cancer death, especially for American men. Most prostate cancers progress very slowly and while on the average about 30% of American males develop prostate cancer, only 3% die from the disease.  The disparity in the statistics indicates that a more effective screening method is required to differentiate the aggressive form of prostate cancer that causes mortality in patients. In this work, a label-free, novel microelectromechanical (MEMS) biosensor for detection of cysteine, a prostate cancer biomarker is presented. This biosensor merges two biosensing techniques, namely resonant frequency measurements and electrochemical impedance spectroscopy (EIS) on a single biosensor. The sensor is based on the innovative placement of the working microelectrodes for EIS technique as the top electrode of a quartz crystal microbalance (QCM) resonator. The QCM acoustic wave sensor consists of a thin AT-cut quartz substrate with two gold electrodes on both sides. The top metal electrode used for generating the acoustic wave is also used for EIS measurements of the biosensor, as illustrated in Fig. 1. The surfaces of the gold electrodes are modified using molecularly-imprinted polymers. Electrochemical methods were used to monitor the self-assembly of cysteine on the gold surface. The thiol-gold self-assembled layer causes impedance and mass change, which was characterised by EIS and acoustic-wave methods, respectively. Preliminary tests were performed on this sensor using cysteine in both phosphate buffer saline and human serum.

  • 159.
    Olugbenga Osikoya, Adeneyi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Vaal University of Technology, South Africa.
    Parlak, Onur
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Bhatia, Ravisha
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Murugan, N. Arul
    Royal Institute of Technology, Sweden.
    Dikio, E. Dixon
    Vaal University of Technology, South Africa.
    Moloto, H.
    Vaal University of Technology, South Africa.
    Uzun, Lokman
    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.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Tekidag AB, Sweden.
    Studies on electrobiocatalytic behaviour of acetylene sourced CVD-synthesised graphene bioelectrodes2016In: Biosensors 2016 – The World Congress on Biosensors, Gothenburg, Sweden, 25-27 May 2016, Elsevier, 2016Conference paper (Other academic)
  • 160.
    Orban, Jenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Griffith, May
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Viter, R
    Linköping University, Faculty of Health Sciences.
    Bechelany, M
    Linköping University, Faculty of Health Sciences.
    Mak, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Surface nanoengineered contact lens as a wearable point-of-care diagnostics platform2014In: 24th Anniversary World Congress on Biosensors – Biosensors 2014, Elsevier, 2014Conference paper (Other academic)
    Abstract [en]

    Detection of biomarkers is essential for disease prevention, diagnosis, and prognosis of early stage treatment. Ocular fluid is an extracellular fluid excreted from the tear gland. Several important markers from ocular fluid have been identified having significant clinical diagnostic value for various diseases. The contact lens is disposable, relatively cheap and serves as a platform to obtain direct intimate contact with ocular fluid and is therefore an attractive and a promising platform for point-of-care diagnostic tests. Here, we present an innovative concept of a wearable contact lens biosensor with nanoengineered biorecognition architecture based on a Layer-by-Layer (LbL) technique on the contact lens surface. This technique enables us to deposit multiple layers of biomolecules to create biorecognition layer under a mild aqueous physiological temperature and pH conditions. The fabrication of the biorecognition layer is simply through physical adsorption and has no restrictions with respect to the substrate size and topology (i.e. contact lens). The thickness of the resulting biorecognition layer is only hundreds of nanometers, and hence has minimal influence on the overall thickness of the contact lens, thus preserving the optical properties of the contact lens for vision correction. We have demonstrated that eye inflammation biomarkers such as interleukin (IL) can be captured in vitro with the contact lens, thus facilitating colorimetric affinity bioassays to measure the amount of interleukin. An in vitro ocular model composed of hydrogel-based artificial cornea and microfluidics was developed to study the performance of the contact lens biosensing platform. The contact  platform was able to detect IL-1α down to the physiological concentration, which is in the range of pg mL-1. There is a recent trend away from handheld devices towards wearable systems, illustrated by popular technology such as “Google glasses” and the “i-Watch”. We believe that the concept of wearable diagnostics holds significant promise as the next generation point-of-care diagnostic platform and that this contact lens-based approach is a convenient platform for a number of important applications.

  • 161.
    Orban, Jenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. 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.
    Griffith, May
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Mak, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Wearable contact lens biosensors with nanoengineered biorecognition layer2013In: BioSensing Technologies, 2013 / [ed] Richard Luxton, Amsterdam: Elsevier, 2013Conference paper (Other academic)
  • 162.
    Osikoya, Adeniyi
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Vanderbijlpark, South Africa.
    Parlak, Onur
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Murugan, N .Arul
    Stockholm, Sweden.
    Dikio, Ezekiel Dixon
    Vanderbijlpark, South Africa.
    Moloto, Harry
    Vanderbijlpark, South Africa.
    Uzun, Lokman
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Department of Chemistry, Hacettepe University, Ankara, Turkey.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. UCS, Tekidag AB, Linkoping,, Sweden; Vinoba Bhave Research Institute, Sirsa Road, Saidabad, Allahabad 221508, India.
    Acetylene-sourced CVD-synthesised catalytically active graphene for electrochemical biosensing.2017In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 89, p. 496-504Article in journal (Refereed)
    Abstract [en]

    In this study, we have demonstrated the use of a graphene sheet as a fundamental building block to obtain a highly ordered graphene-enzyme electrode for electrochemical biosensing. Firstly, thin graphene sheets were deposited on 1.00 mm thick copper sheet at 850 oC, via chemical vapour deposition (CVD), using acetylene (C2H2) as carbon source in an argon (Ar) and nitrogen (N2) atmosphere. An anionic surfactant was used to introduce electrostatic charges and increase wettability and hydrophilicity on the basal plane of the otherwise hydrophobic graphene, thereby facilitating the assembly of biomolecules on the graphene surface. The bioelectrocatalytic activity of the system was investigated by the assembly of glucose oxidase (GOx) on the surface of the graphene sheet by intermolecular attractive forces. The electrochemical sensing activity of the graphene-based system was explored as a model for bioelectrocatalysis. The bioelectrode exhibited a linear response to glucose concentration from 0.2 to 9.8 mM, with sensitivity of 0.087 µA/µM/cm2 and a detection limit of 0.12 µM (S/N=3). This work sets the stage for the use of acetylene-sourced graphene sheets as fundamental building blocks in the fabrication of electrochemical biosensors and other biocatalytic devices.

  • 163.
    OWEN, VM
    et al.
    CRANFIELD INST TECHNOL,CTR BIOTECHNOL,DIV BIOELECTR,CRANFIELD MK43 0AL,BEDS,ENGLAND; .
    TURNER, APF
    Cranfield University, UK.
    BIOSENSORS - A REVOLUTION IN CLINICAL ANALYSIS1987In: Endeavour, ISSN 0160-9327, E-ISSN 1873-1929, Vol. 11, no 2, p. 100-104Article in journal (Refereed)
    Abstract [en]

    n/a

  • 164.
    Ozgur, Edogan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Hacettepe University, Turkey.
    Patra, Hirak Kumar
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Uzun, Lokman
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Hacettepe University, Turkey.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Smart polymerisable terbium (III) complex-based fluorescent MIP nanoparticles2016In: Biosensors 2016 – The World Congress on Biosensors, Gothenburg, Sweden, 25-27 May 2016, Elsevier, 2016Conference paper (Other academic)
  • 165.
    Pal Basak, Sreela
    et al.
    University of Calcutta, India .
    Kanjilal, Baishali
    University of Calcutta, India .
    Sarkar, Priyabrata
    University of Calcutta, India .
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Application of electrical impedance spectroscopy and amperometry in polyaniline modified ammonia gas sensor2013In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 175, p. 127-133Article in journal (Refereed)
    Abstract [en]

    Accurate and fast detection of ammonia gas is a highly desirable requisite in environmental gas analysis, the automotive industry, the chemical industry and for medical applications. In this study a cost effective and portable electrochemical ammonia (NH3) gas sensor is reported. The sensor was based on polyaniline (PANI) nanofibres employing the techniques of electrical impedance spectroscopy with frequency response analysis and amperometry. PANI is well known for its interaction with ammonia gas. This conducting polymer (PAN!) of the semi-flexible rod polymer family, is unique due to its easy synthesis method, environmental stability, and simple doping/dedoping chemistry. PANI was synthesized and characterized by SEM, FTIR, XRD and AFM studies. The experimental data were used to explain, characterize and standardize the changes, upon exposure to ammonia gas, in the resistive and capacitative components set up in the PANI electrochemical cell. This nondestructive chemical-gas sensor was characterized by high sensitivity, a wide range of measured concentrations (0-20 ppm) in case of EIS and (2.5-20 ppm) in case of amperometry, reliability and reproducibility of the sensing data.

  • 166.
    Palchetti, I
    et al.
    UNIV FLORENCE, DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALIT, I-50121 FLORENCE, ITALY; CRANFIELD UNIV, CRANFIELD BIOTECHNOL CTR, CRANFIELD MK43 0AL, BEDS, ENGLAND; ARPAT, DIPARTIMENTO PROV PISTOIA, PISTOIA, ITALY; .
    Cagnini, A
    UNIV FLORENCE, DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALIT, I-50121 FLORENCE, ITALY; CRANFIELD UNIV, CRANFIELD BIOTECHNOL CTR, CRANFIELD MK43 0AL, BEDS, ENGLAND; ARPAT, DIPARTIMENTO PROV PISTOIA, PISTOIA, ITALY; .
    DelCarlo, M
    UNIV FLORENCE, DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALIT, I-50121 FLORENCE, ITALY; CRANFIELD UNIV, CRANFIELD BIOTECHNOL CTR, CRANFIELD MK43 0AL, BEDS, ENGLAND; ARPAT, DIPARTIMENTO PROV PISTOIA, PISTOIA, ITALY; .
    Coppi, C
    UNIV FLORENCE, DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALIT, I-50121 FLORENCE, ITALY; CRANFIELD UNIV, CRANFIELD BIOTECHNOL CTR, CRANFIELD MK43 0AL, BEDS, ENGLAND; ARPAT, DIPARTIMENTO PROV PISTOIA, PISTOIA, ITALY; .
    Mascini, M
    UNIV FLORENCE, DIPARTIMENTO SANITA PUBBL EPIDEMIOL and CHIM ANALIT, I-50121 FLORENCE, ITALY; CRANFIELD UNIV, CRANFIELD BIOTECHNOL CTR, CRANFIELD MK43 0AL, BEDS, ENGLAND; ARPAT, DIPARTIMENTO PROV PISTOIA, PISTOIA, ITALY; .
    Turner, APF
    Cranfield University, UK.
    Determination of anticholinesterase pesticides in real samples using a disposable biosensor1997In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 337, no 3, p. 315-321Article in journal (Refereed)
    Abstract [en]

    A choline amperometric biosensor based on screen-printed electrodes was assembled and used to assess the inhibitory effect of organophosphorus and carbamic pesticides on acetylcholinesterase activity both in standard solutions and real samples, Acetylcholinesterase catalyses the cleavage of acetylcholine to choline and acetate, therefore the amount of choline measured using the biosensor is directly related to the enzyme activity. The extent of enzyme inhibition can be used as an index of the amount of anticholinesterase pesticides present. The hydrophobicity of organophosphorus and carbamic pesticides led to the evaluation of organic, water miscible solvents for use in the proposed method. Berate buffer containing 1% v/v acetonitrile was selected since it exhibited the least influence on enzyme activity from the tested solvents (acetonitrile, acetone, tetrahydrofuran and ethylacetate). Other solvents (dimethylsulfoxide and methanol) were avoided as they exhibited electrochemical interferences. An inhibition calibration curve was obtained using carbofuran, a strong inhibitor of acetylcholinesterase. The lowest detectable standard solution (mean +/-3 standard deviation of the blank) was 2 mu gl(-1) following an incubation time of 10 min. The method was then applied to real samples (fruits and vegetables) showing its suitability as a rapid screening assay (12 min per test) for the assessment of anticholinesterase pesticides, The biosensor results were compared with a standard analytical technique (gas chromatography with nitrogen phosphorus detector, GC-NPD).

  • 167.
    Palchetti, I
    et al.
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Anal A, I-50121 Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; .
    Cagnini, A
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Anal A, I-50121 Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; .
    Mascini, M
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Anal A, I-50121 Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; .
    Turner, APF
    Cranfield University, UK.
    Characterisation of screen-printed electrodes for detection of heavy metals1999In: Mikrochimica Acta, ISSN 0026-3672, E-ISSN 1436-5073, Vol. 131, no 02-jan, p. 65-73Article in journal (Refereed)
    Abstract [en]

    The characterisation of disposable screen-printed electrodes for stripping analysis is described. The graphite surface of the working electrode is used as substrate for plating a thin mercury film, which allows the electrochemical preconcentration of heavy metals. Optimisation procedures and experimental results are presented. Detection limits around the ppb level were obtained for different metals [Pb(II), Cd(II), Cu(II)].

  • 168.
    Palchetti, I
    et al.
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, I-50121 Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 OAL, Beds, England; .
    Upjohn, C
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, I-50121 Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 OAL, Beds, England; .
    Turner, APF
    Cranfield University, UK.
    Mascini, M
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, I-50121 Florence, Italy; Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 OAL, Beds, England; .
    Disposable screen-printed electrodes (SPE) mercury-free for lead detection2000In: Analytical Letters, ISSN 0003-2719, E-ISSN 1532-236X, Vol. 33, no 7, p. 1231-1246Article in journal (Refereed)
    Abstract [en]

    Strategies to modify screen-printed electrodes (SPE) for lead determination are reported. Dithizone was mixed with graphite ink to obtain a modified screen-printed strip to detect ppb levels of lead(II) (detection limit 12 mu g/l) using square wave anodic stripping voltammetry (SWASV). In addition, screen-printed electrodes were also modified by casting a few mu l of a Nafion(R) solution onto the working electrode surface. In this case, ppb levels of lead were detected (detection limit 15 mu g/l), using potentiometric stripping analysis (PSA). The addition of an ionophore to Nafion(R) polymer was also investigated, but this did not yield a significant improvement.

  • 169.
    Palleschi, G.
    et al.
    Cranfield Institute of Technology, Biotechnology Centre, Cranfield, Bedford , UK.
    Turner, Anthony P. F.
    Cranfield University, UK.
    Amperometric tetrathiafulvalene-mediated lactate electrode using lactate oxidase absorbed on carbon foil1990In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 234, no 2, p. 459-463Article in journal (Other academic)
    Abstract [en]

    The features of a new sensor for determining l-lactate are reported. The enzyme lactate oxidase and the mediator, tetrathiafulvalene (TTF), are absorbed on carbon foil disks previously bonded onto the ends of glass tubes. Linear calibration graphs were obtained in the range 10−4−10−3 M with physiological phosphate buffer (pH 7.35) and at 30°C with a response time of a few seconds. Calibration graphs in the range 10−3−10−2 M were also obtained and the difference in response times between these two ranges were investigated. The results are promising for assembling disposable lactate sensors for in vitro or for in or ex vivo measurements.

  • 170.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Ashaduzzaman, Md.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of Dhaka, Bangladesh.
    Kollipara, Suresh B.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. UCS, Tekidag AB, SE-58330 Linkoping, Sweden.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Switchable Bioelectrocatalysis Controlled by Dual Stimuli-Responsive Polymeric Interface2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 43, p. 23837-23847Article in journal (Refereed)
    Abstract [en]

    The engineering of bionanointerfaces using stimuli-responsive polymers offers a new dimension in the design of novel bioelectronic interfaces. The integration of electrode surfaces with stimuli-responsive molecular cues provides a direct control and ability to switch and tune physical and chemical properties of bioelectronic interfaces in various biodevices. Here, we report a dual-responsive biointerface employing a positively responding dual-switchable polymer, poly(NIPAAm-co-DEAEMA)-b-HEAAm, to control and regulate enzyme-based bioelectrocatalysis. The design interface exhibits reversible activation deactivation of bioelectrocatalytic reactions in response to change in temperature and in pH, which allows manipulation of biomolecular interactions to produce on/off switchable conditions. Using electrochemical measurements, we demonstrate that interfacial bioelectrochemical properties can be tuned over a modest range of temperature (i.e., 20-60 degrees C) and pH (i.e., pH 4-8) of the medium. The resulting dual-switchable interface may have important implications not only for the design of responsive biocatalysis and on-demand operation of biosensors, but also as an aid to elucidating electron-transport pathways and mechanisms in living organisms by mimicking the dynamic properties of complex biological environments and processes.

  • 171.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beyazit, Selim
    CNRS Enzyme and Cell Engineering Laboratory, Université de Technologie de Compiègn Rue Roger Couttolenc, Compiègne, Cedex, France.
    Jafari, Mohammed J.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Tse Sum Bui, Bernadette
    CNRS Enzyme and Cell Engineering Laboratory, Université de Technologie de Compiègn Rue Roger Couttolenc, Compiègne, Cedex, France.
    Haupt, Karsten
    CNRS Enzyme and Cell Engineering Laboratory, Université de Technologie de Compiègn Rue Roger Couttolenc, Compiègne, Cedex, France.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Tekidag AB, UCS, Linköping, Sweden.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Light-triggered switchable graphene-polymer hybrid bioelectronics2016In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 3, no 2, p. 1500353-1-1500353-7Article in journal (Refereed)
    Abstract [en]

    A light-switchable graphene interface to control and regulate electrobiocatalysis in a nanoconfined space is reported for the first time. The development of switchable and/or tunable interfaces on 2D nanosurfaces endowed with desirable functionalities, and incorporation of these interfaces into remote controlled biodevices, is a rapidly emerging area in bioelectronics.

  • 172.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beyazit, Selim
    Sorbonne Universités, Université de Technologie de Compiègne, CNRS Laboratory for Enzyme and Cell Engineering, France.
    Jafari, Mohammed J.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Tse Sum Bui, Bernadette
    Sorbonne Universités, Université de Technologie de Compiègne, CNRS Laboratory for Enzyme and Cell Engineering, France.
    Haupt, Karsten
    Sorbonne Universités, Université de Technologie de Compiègne, CNRS Laboratory for Enzyme and Cell Engineering, France.
    Tiwari, Ashutosh
    Tekidag AB, UCS, Mjärdevi Science Park, Linköping Sweden.
    Turner, Anthony P. F
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Light-triggered on/off-switchable graphene-based bioelectronicsManuscript (preprint) (Other academic)
  • 173.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beyazit, Selim
    Sorbonne Universités, Université de Technologie de Compiègne, CNRS Laboratory for Enzyme and Cell Engineering, France.
    Tse Sum Bui, Bernadette
    Sorbonne Universités, Université de Technologie de Compiègne, CNRS Laboratory for Enzyme and Cell Engineering, France.
    Haupt, Karsten
    Sorbonne Universités, Université de Technologie de Compiègne, CNRS Laboratory for Enzyme and Cell Engineering, France.
    Turner, Anthony P. F
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Tekidag AB, UCS, Mjärdevi Science Park, Linköping Sweden.
    Programmable bioelectronics in a stimuli-encoded 3D grapheneManuscript (preprint) (Other academic)
  • 174.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beyazit, Selim
    Compiègne Cedex, France.
    Tse Sum Bui, Bernadette
    Compiègne Cedex, France.
    Haupt, Karsten
    Compiègne Cedex, France.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Vinoba Bhave Research Institute, Sirsa Road, Saidabad, India .
    Programmable bioelectronics in a stimuli-encoded 3D graphene interfaces2016In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 8, p. 9976-9981Article in journal (Refereed)
    Abstract [en]

    The ability to program and mimic the dynamic microenvironment of living organisms is a crucial step towards the engineering of advanced bioelectronics. Here, we report for the first time a design for programmable bioelectronics, with ‘built-in’ switchable and tunable bio-catalytic performance that responds simultaneously to appropriate stimuli. The designed bio-electrodes comprise light and temperature responsive compartments, which allow the building of Boolean logic gates (i.e. “OR” and “AND”) based on enzymatic communications to deliver logic operations.

  • 175.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Incel, Anil
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Uzun, Lokman
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Biochemistry Division, Department of Chemistry, Hacettepe University, Ankara, Turkey.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Structuring Au nanoparticles on two-dimensional MoS2 nanosheets for electrochemical glucose biosensors.2017In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 89, no 1, p. 545-550Article in journal (Refereed)
    Abstract [en]

    Two-dimensional (2D) bioelectronics is an emerging field of research which fuses the advantages of 2D nanomaterials with those of nanobiotechnology. Due to the various physical and chemical properties present in layered counterparts of 2D materials, including high charge density, large surface area, remarkable electron mobility, ready electron transport, sizeable band gaps and ease of hybridisation, they are set to become a versatile tool to fabricate sensitive and selective novel biodevices, which might offer an unique advantages to tackle key energy, medical and environmental issues. Current 2D bioelectronics research is focused on the design of simple-to-use and cheaper biodevices, while improving their selectivity, sensitivity and stability. However, current designs generally suffer from a lack of efficiency, relatively low sensitivity, slow electron transfer kinetics, high background charging current and low current density arising from poor mass transport. Here, we report a nanoparticle-structured MoS2 nanosheet as an ideal semiconductor interface, which is able to form a homogenous layer on the electrode surface for the assembly of gold nanoparticles. This not only enhances electrocatalytic reactions, but also provides excellent electrochemical properties such as high faradic-to-capacitive current ratios, high current density and electron mobility, and faster mass transport, due to the dominance of radial diffusion. The MoS2/Au NPs/GOx bioelectrode exhibits a linear response to glucose from 0.25 to 13.2 mM, with a detection limit of 0.042 µM (S/N=3) and sensitivity of 13.80 µA/µM/cm2.

  • 176.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mishra, Yogendra K.
    Functional Nanomaterials, Institute for Materials Science, Christian-Albrechts Universität zu Kiel, Kiel, Germany.
    Grigoriev, Anton
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Mecklenburg, Matthias
    Institute of Polymers and Composites, Hamburg University of Technology, Hamburg, Germany.
    Schulte, Karl
    Institute of Polymers and Composites, Hamburg University of Technology, Hamburg, Germany.
    Ahuja, Rajeev
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Adelung, Rainer
    Functional Nanomaterials, Institute for Materials Science, Christian-Albrechts Universität zu Kiel, Kiel, Germany.
    Turner, Anthony P. F.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Tekidag AB, UCS, Mjärdevi Science Park, Linköping Sweden.
    Probing electrocatalytic properties of aerographite for the design of flexible bio-electrodeManuscript (preprint) (Other academic)
  • 177.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mishra, Yogendra Kumar
    Functional Nanomaterials, Institute for Materials Science, Kiel University, Kiel, Germany.
    Grigoriev, Anton
    Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Mecklenburg, Matthias
    e Institute of Polymers and Composites, Hamburg University of Technology, Hamburg, Germany.
    Luo, Wei
    d Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Keene, Scott
    Department of Materials Science and Engineering, Stanford University, Stanford, USA.
    Salleo, Alberto
    Department of Materials Science and Engineering, Stanford University, Stanford, USA.
    Schulte, Karl
    e Institute of Polymers and Composites, Hamburg University of Technology, Hamburg, Germany.
    Ahuja, Rajeev
    d Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Hierarchical Aerographite Nano-Microtubular Tetrapodal Networks based Electrodes as Lightweight Supercapacitor.2017In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 34, p. 570-577Article in journal (Refereed)
    Abstract [en]

    A great deal of interest has been paid to the application of carbon-based nano- and microstructured materials as electrodes due to their relatively low-cost production, abundance, large surface area, high chemical stability, wide operating temperature range, and ease of processing including many more excellent features. The nanostructured carbon materials usually offer various micro-textures due to their varying degrees of graphitisation, a rich variety in terms of dimensionality as well as morphologies, extremely large surface accessibility and high electrical conductivity, etc. The possibilities of activating them by chemical and physical methods allow these materials to be produced with further higher surface area and controlled distribution of pores from nanoscale upto macroscopic dimensions, which actually play the most crucial role towards construction of the efficient electrode/electrolyte interfaces for capacitive processes in energy storage applications. Development of new carbon materials with extremely high surface areas could exhibit significant potential in this context and motivated by this in present work, we report for the first time the utilization of ultralight and extremely porous nano-microtubular Aerographite  tetrapodal network as a functional interface to probe the electrochemical properties for capacitive energy storage. A simple and robust electrode fabrication strategy based on surface functionalized Aerographite with optimum porosity leads to significantly high specific capacitance (640 F/g) with high energy (14.2 Wh/kg) and power densities (9.67x103 W/kg) which has been discussed in detail.

  • 178.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Seshadri, Preeethi
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. 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.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Structuring of nanoelectrode array of Au nanoparticle on two-dimensional WS2 interface for electrochemical biosensing2014In: 24th Anniversary World Congress on Biosensors – Biosensors 2014, Elsevier, 2014Conference paper (Other academic)
    Abstract [en]

    The reduction in size of an electrode improves the mass transport of molecules to the electrode surface because of the contribution of radial diffusion. Thus, nanoelectrodes are particularly well suited for electroanalytical applications [1]. However, the construction of nanoelectrodes generally involve specialised equipment that is relatively complex to fabricate and not suitable for mass production. However nanostructuring of macroelectrode surface by metallic nanoparticles have been recently used in a variety of biosensing applications due to their enhanced surface area, precise biomolecule-electrode connections. For electrochemical sensing, conductive nanostructures immobilised on electrodes enhance electrocatalytic behaviour due the quantum confinement and exhibit unique features including favourable Faradic-to-capacitive current ratios, higher current densities and faster mass transport by convergent diffusion than their larger micro/macro electrode counterparts. In order to increase biosensor current output to measurable levels, large arrays of nanostructures have been immobilised on electrode surface [2]. The nanoelectrode arrays biosensors have been fabricated by various nanostructures such as nanowires, nanotubes and nanoparticles, have demonstrated promising results, displaying high sensitivity and fast response time.

           In this study, we present a new nanostructured biosensor to address many limitations that nanoelectrode array biosensors currently face. Here, we used WS2-Au nanoparticle self-assembled structures as an interface element for electrochemical sensing of H2O2. The combination of zero-dimension nanoparticles on a two-dimensional support that is arrayed in the third dimension creates a biosensor platform with exceptional characteristics. The versatility of the biosensor platform was demonstrated by altering biosensor performance with a sensitivity (11.64 µA/µM/cm2), detection limit (0.085 µM), and linear sensing range (0.05-12.0 mM). This promising approach provides a novel methodology for structuring of Au nanoarray on two-dimensional surface and furnishes the basis for fabrication of flexible ultra-sensitive and efficient electrochemical biosensors.

     

  • 179.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Seshadri, Prethi
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Turner, Anthony P.F.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Two-dimensional gold-tungsten disulphide bio-interface for high-throughput electrocatalytic nano-bioreactors2014In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 1, no 6, p. 1400136-Article in journal (Refereed)
    Abstract [en]

    A high-throughput electrocatalytic nano-bioreactor on tungsten disulphide nanosheets is demonstrated for the first time. The fundamental goal of this research is to develop a higher surface area, resulting in a greater enzyme loading and thereby increasing bio-catalytic activity within a nano-confined volume. As a result, the nanobio-system is capable of highly specific recognition of target bioanalytes, therefore, showing significant potentials in a range of bioreactor applications.

  • 180.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Electro-catalytic nanoparticle-polymer fibre networks for efficient bioenergy devices.2015In: 1st International Conference on Green Chemistry and Sustainable Technologies, 2015Conference paper (Refereed)
  • 181.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    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.
    Switchable Bioelectronics on a Graphene Interface2015In: 2nd International Biosensor Congress, 2015Conference paper (Other academic)
  • 182.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Switchable bioelectronics on graphene interface.2015In: Biosensing and Nanomedicine-VIII at SPIE Optics and Photonics, San Diego, CA, 9-13 August 2015., 2015Conference paper (Refereed)
    Abstract [en]

    Smart and flexible bioelectronics on graphene have emerged as a new frontier in the field of biosensors and bioelectronics. Graphene has begun to be seen as an ideal signal transducer and a promising alternative for the production of low-cost bioelectronic devices.1-2 However, biological systems used in these devices suffer from a lack of control and regulation. There is an obvious need to develop “switchable” and “smart” interfaces for both fundamental and applied studies. Here, we report the fabrication of a stimuli-responsive graphene interface, which is used to regulate biomolecular reactions.

    The present study aims to address the design and development of a novel auto-switchable graphene bio-interface that is capable of positively responding, by creating smart nanoarchitectures. The smart bio-interface consists of a two-dimensional graphene donor and a polymeric receptor, which are rationally assembled together based in a stoichiometric donor-receptor interaction. By changing the external conditions such as temperature, light and pH of the medium, we acheived control of the biochemical interactions. In the negative mode, access of an associated enzyme to its substrate is largely restricted, resulting in a decrease in the diffusion of reactants and the consequent activity of the system. In contrast, the biosubstrate could freely access the enzyme facilitating bioelectrocatalysis in a positive response. More importantly, this provides the first example of responsive bioelectronics being achieved on a two-dimensional graphene interface by controlling the various external stimuli in an on/off-switchable model.

    Using electrochemical techniques, we demonstrated that interfacial bio-electrochemical properties can be tuned by modest changes in conditions. Such an ability to independently regulate the behaviour of the interface has important implications for the design of novel bioreactors, biofuel cells and biosensors with inbuilt self-control features.

    Reference:

    [1] O. Parlak, A. P. F. Turner, A. Tiwari, Advanced Materials, 3 (2014), 482.

    [2] O. Parlak, A. Tiwari, A. P. F. Turner, A. Tiwari, Biosensors and Bioelectronics 49         (2013), 53.

  • 183.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Atul
    Hawaii Corrosion Laboratory, Department of Mechanical Engineering, University of Hawaii at Manoa, 96822 Hawaii, USA.
    Turner, Anthony P. F.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Template-Directed Hierarchical Self-Assembly of Graphene Based Hybrid Structure for Electrochemical Biosensing2013In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 49, p. 53-62Article in journal (Refereed)
    Abstract [en]

    A template-directed self-assembly approach, using functionalised graphene as a fundamental building block to obtain a hierarchically ordered graphene-enzyme-nanoparticle bioelectrode for electrochemical biosensing, is reported. An anionic surfactant was used to prepare a responsive, functional interface and direct the assembly on the surface of the graphene template. The surfactant molecules altered the electrostatic charges of graphene, thereby providing a convenient template-directed assembly approach to a free-standing planar sheet of sp(2) carbons. Cholesterol oxidase and cholesterol esterase were assembled on the surface of graphene by intermolecular attractive forces while gold nanoparticles are incorporated into the hetero-assembly to enhance the electro-bio-catalytic activity. Hydrogen peroxide and cholesterol were used as two representative analytes to demonstrate the electrochemical sensing performance of the graphene-based hybrid structure. The bioelectrode exhibited a linear response to H2O2 from 0.01 to 14 mM, with a detection limit of 25 nM (S/N=3). The amperometric response with cholesterol had a linear range from 0.05 to 0.35 mM, sensitivity of 3.14 mu A/mu M/cm(2) and a detection limit of 0.05 mu M. The apparent Michaelis-Menten constant (K-m(app)) was calculated to be 1.22 mM. This promising approach provides a novel methodology for template-directed bio-self-assembly over planar sp(2) carbons of a graphene sheet and furnishes the basis for fabrication of ultra-sensitive and efficient electrochemical biosensors.

  • 184.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony P. F.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Tekidag AB, UCS, Mjärdevi Science Park, Linköping Sweden.
    pH-induced on/off-switchable graphene bioelectronics2015In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 3, no 37, p. 7434-7439Article in journal (Refereed)
    Abstract [en]

    Switchable interfaces can deliver functionally reversible reactivity with their corresponding analytes, which thus allows one to positively respond the activity of biological elements, including enzymes and other biomolecules, through an encoded stimulus. We have realised this by the design of stimuli-responsive graphene interfaces for pH-encoded operation of bioelectronics. In this study, we have demonstrated stimuli-responsive graphene interfaces for pH-encoded operation of bioelectronics. The resulting switchable interfaces are capable of highly specific, on-demand operation of biosensors, which has significant potential in a wide range of analytical applications.

  • 185.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony P.F.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Switchable bioelectronics2016In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 76, p. 251-265Article in journal (Refereed)
    Abstract [en]

    We review the rapidly emerging field of switchable interfaces and its implications for bioelectronics. We seek to piece together early breakthroughs and key developments, and highlight and discuss the future of switchable bioelectronics by focusing on bio-electrochemical processes based on mimicking and controlling biological environments with external stimuli. All these studies strive to answer a fundamental question: “how do living systems probe and respond to their surroundings? And, following on from that: “how one can transform these concepts to serve the practical world of bioelectronics?” The central obstacle to this vision is the absence of versatile interfaces that are able to control and regulate the means of communication between biological and electronic systems. Here, we review the overall progress made to date in building such interfaces at the level of individual biomolecules and focus on the latest efforts to generate device platforms that integrate bio-interfaces with electronics.

  • 186.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. 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.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    On/off-switchable zipper-like bioelectronics on a graphene interface.2014In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, no 3, p. 482-486Article in journal (Refereed)
    Abstract [en]

    An on/off-switchable graphene based zipper-like interface is architectured for efficient bioelectrocatalysis. The graphene interface transduces a temperature input signal into structural changes of the membrane, resulting in the amplification of electrochemical signals and their transformation into the gated transport of molecules through the membrane.

  • 187.
    Parlak, Onur
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. 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.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Switchable bioelectronics on a graphene interface2014In: 24th Anniversary World Congress on Biosensors – Biosensors 2014, Elsevier, 2014Conference paper (Other academic)
    Abstract [en]

    Smart and flexible bioelectronics on graphene have emerged as a new frontier in the field of biosensors and bioelectronics [1]. Graphene has begun to be seen as an ideal signal transducer and a promising alternative for the production of low-cost bioelectronic devices. However, biological systems used in these devices suffer from a lack of control and regulation. There is an obvious need to develop “switchable” and “smart” interfaces for both fundamental and applied studies [2]. Here, we report for the first time the fabrication of an on/off-switchable graphene interface, which is used to regulate biomolecular reactions.

        The present study aims to address the design and development of a novel auto-switchable graphene bio-interface that is capable of positively responding, by creating unique “zipper” nanoarchitectures. The zipper consists of a two-dimensional graphene donor and a polymeric receptor, which are rationally assembled together based in a stoichiometric donor-receptor interaction. Preferably, at a relatively low temperature (20 oC) the active donor-receptor interaction (hydrogen bonding) creates a coalescence of the graphene interface, thereby causing considerable shrinkage in the donor-to-receptor interface. Thus access of an associated enzyme to its substrate is largely restricted, resulting in a decrease in the diffusion of reactants and the consequent activity of the system. In contrast, at a comparatively high temperature (40 oC) the donor-receptor interaction was subverted. As a result, the biosubstrate could freely access the enzyme facilitating bioelectrocatalysis. More importantly, this provides the first example of responsive bioelectronics being achieved on a two-dimensional graphene interface by controlling the external temperature as an on/off-switchable model.

         Using electrochemical techniques, we demonstrated that interfacial bio-electrochemical properties can be tuned by modest changes in temperature. Such an ability to independently regulate the behaviour of the interface has important implications for the design of novel bioreactors, biofuel cells and biosensors with inbuilt self-control features.

     

  • 188.
    Patra, Hirak
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Imani, Roghayeh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Iglic, Ales
    Biophysics Laboratory, Faculty of Electrical Engineering, University of Ljubljana, Slovenia.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Novel anti-neoplastic approach for photodynamic theranostics by biocompatible TiO2 popcorn nanostructure for a high-throughput flash ROS generator2014In: 24th Anniversary World Congress on Biosensors – Biosensors 2014, Elsevier, 2014Conference paper (Refereed)
    Abstract [en]

    Reactive oxygen species (ROS) are important secondary messengers in the intracellular signaling system for regulating redox homeostasis in normal cells. Compared to normal cells, cancer cells have increased ROS levels due to a faster metabolic rate. We have used this discriminating overproduction of ROS levels in cancer cells  as a target for a photodynamic anti-neoplastic theranostic approach using mesoporous TiO2 microbeads with a popcorn nanostructure. We have created a novel flash ROS generator  using a two-step procedure consisting of sol-gel and solvothermal processes to obtain mesoporous TiO2 microbeads with high photocatalytic efficiency. A photon-induced comparative study has been carried out for the ROS generation ability using TiO2 nanoparticles and mesoporous TiO2 microbeads.  We have shown that in under otherwise identical conditions the extent of photocatalytical ROS generated by mesoporous TiO2 microbeads is more than twice that produced by TiO2 nanoparticles. In vitro in the absence of irradiation, the mesoporous TiO2 microbeads are exceptionally biocompatible, allowing almost ~100% cellular survival rate even at a dose of 100 µg/mL. In contrast, commercial nanoparticles showed concentration dependent cytotoxicity of nearly 15% within 24h in the absence of any irradiation. Upon photo activation, the mesoporous TiO2 microbead structures delivered their potential anticancer effect by interfering with the mitochondrial activity by producing ROS in the intracellular environment and thus reducing the survival rate of cells by more than 30% in comparison with commercial nanoparticles, where only an increase of 5% in cell death was observed. Thus we have developed a smart on/off switchable photodynamic anti-neoplastic theranostic approach that can be combined with specific cell recognition elements for future cancer management.

  • 189.
    Patra, Hirak K.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology. Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    The potential legacy of cancer nanotechnology: celluar selection2014In: Trends in Biotechnology, ISSN 0167-7799, E-ISSN 1879-3096, Vol. 32, no 1, p. 21-31Article, review/survey (Refereed)
    Abstract [en]

    Overexpression of oncogenes or loss of tumour suppressors can transform a normal cell to a cancerous one, resulting in uncontrolled regulation of intracellular signalling pathways and immunity to stresses, which both pose therapeutic challenges. Conventional approaches to cancer therapy, although they are effective at killing cancer cells, may still fail due to inadequate biodistribution and unwanted side effects. Nanotechnology-based approaches provide a promising alternative, with the possibility of targeting cells at an early stage, during their transformation into cancer cells. This review considers techniques that specifically target those molecular changes, which begin in only a very small percentage of normal cells as they undergo transformation. These techniques are crucial for early-stage diagnosis and therapy.

  • 190.
    Patra, Hirak Kumar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Imani, Roghayeh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Univ,of Ljubljana, Slovenia; University of Ljubljana, Slovenia.
    Jangamreddy, Jaganmohan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Pazoki, Meysam
    Uppsala University, Sweden.
    Iglic, Ales
    University of Ljubljana, Slovenia.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. Tekidag AB, SE-58330 Linkoping, Sweden.
    On/off-switchable anti-neoplastic nanoarchitecture2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, no 14571, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO2 Pops) nanoarchitecture. The resulting TiO2 Pops, unlike TiO2 nanoparticles (TiO2 NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO2 Pops show very high photocatalytic activity compared to TiO2 NPs. Upon on/off-switchable photo activation, the TiO2 Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the death gate, thus reducing the survival of cancer cells by at least six times in comparison with TiO2 NPs without affecting the normal cells.

  • 191.
    Patra, Hirak Kumar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Khaliq, Nisar Ul
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Romu, Thobias
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Wiechec, Emilia
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Turner, Anthony P. F.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    MRI-Visual Order–Disorder Micellar Nanostructures for Smart Cancer Theranostics2014In: Advanced Healthcare Materials, ISSN 2192-2640, Vol. 3, no 4, p. 526-535Article in journal (Refereed)
    Abstract [en]

    The development of MRI-visual order–disorder structures for cancer nanomedicine explores a pH-triggered mechanism for theragnosis of tumor hallmark functions. Superparamagnetic iron oxide nanoparticles (SPIONs) stabilized with amphiphilic poly(styrene)-b-poly(acrylic acid)-doxorubicin with folic acid (FA) surfacing are employed as a multi-functional approach to specifically target, diagnose, and deliver drugs via a single nanoscopic platform for cancer therapy. The functional aspects of the micellar nanocomposite is investigated in vitro using human breast SkBr3 and colon cancer HCT116 cell lines for the delivery, release, localization, and anticancer activity of the drug. For the first time, concentration-dependent T2-weighted MRI contrast for a monolayer of clustered cancer cells is shown. The pH tunable order–disorder transition of the core–shell structure induces the relative changes in MRI contrast. The outcomes elucidate the potential of this material for smart cancer theranostics by delivering non-invasive real-time diagnosis, targeted therapy, and monitoring the course and response of the action before, during, and after the treatment regimen.

  • 192.
    Patra, Hirak Kumar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics.
    Sharma, Yashpal
    International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), Sengen, Tsukuba, Ibaraki, Japan .
    Islam, Mohammad Mirazul
    Swedish Nanoscience Center, Karolinska Institute, Stockholm, Sweden.
    Jafari, Mohammad Javad
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Arul Murugan, N.
    Virtual Laboratory for Molecular Probes, Division of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology (KTH), Stockholm, Sweden .
    Kobayashi, Hisatoshi
    International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), Sengen, Tsukuba, Ibaraki, Japan .
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), Sengen, Tsukuba, Ibaraki, Japan ; Tekidag AB, UCS, Linköping, Sweden; Vinoba Bhave Research Institute, Saidabad, Allahabad, India .
    Inflammation-sensitive in situ smart scaffolding for regenerative medicine2016In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 8, no 39, p. 17213-17222Article in journal (Refereed)
    Abstract [en]

    To cope with the rapid evolution of the tissue engineering field, it is now essential to incorporate the use of on-site responsive scaffolds. Therefore, it is of utmost importance to find new Intelligent biomaterials that can respond to the physicochemical changes in the microenvironment. In this present report, we have developed biocompatible stimuli responsive polyaniline-multiwalled carbon nanotube/poly(N-isopropylacrylamide), (PANI-MWCNT/PNIPAm) composite nanofiber networks and demonstrated the physiological temperature coordinated cell grafting phenomenon on its surface. The composite nanofibers were prepared by a two-step process initiated with an assisted in situ polymerization followed by electro-spinning. To obtain a smooth surface in individual nanofibers with the thinnest diameter, the component ratios and electrospinning conditions were optimized. The temperature-gated rearrangements of the molecular structure are characterized by FTIR spectroscopy with simultaneous macromolecular architecture changes reflected on the surface morphology, average diameter and pore size as determined by scanning electron microscopy. The stimuli responsiveness of the nanofibers has first been optimized with computational modeling of temperature sensitive components (coil-like and globular conformations) to tune the mechanism for temperature dependent interaction during in situ scaffolding with the cell membrane. The nanofiber networks show excellent biocompatibility, tested with fibroblasts and also show excellent sensitivity to inflammation to combat loco-regional acidosis that delay the wound healing process by an in vitro model that has been developed for testing the proposed responsiveness of the composite nanofiber networks. Cellular adhesion and detachment are regulated through physiological temperature and show normal proliferation of the grafted cells on the composite nanofibers. Thus, we report for the first time, the development of physiological temperature gated inflammation-sensitive smart biomaterials for advanced tissue regeneration and regenerative medicine.

  • 193.
    Patra, Hirak Kumar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Valyukh, Sergiy
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, Faculty of Science & Engineering.
    Wiechec, Emilia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Tiwari, Ashutosh
    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.
    Switchable label free apta-nanosensor: In situ biopsy?2016In: Biosensors 2016 – The World Congress on Biosensors, Gothenburg, Sweden, 25-27 May 2016, Elsevier, 2016Conference paper (Other academic)
  • 194.
    Patra, Hirak
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. 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.
    Smart inflammation sensitive self-reporting theragnosis2014In: FEBS-EMBO 2014 Congress, 2014Conference paper (Other academic)
    Abstract [en]

    We have designed and develop a novel class of nanocomposites for inflammation based hallmark functions using biocompatible metallic nano-objects (SPION, nanorod) assembled with a pH sensitive amphiphilic azide terminated block polymer, polystyrene-b-poly (acrylic acid) and temperature-responsive polymer Poly (N-isopropylacrylamide) (PNIPAAm) in a single nanoscopic platform. The nano-architecture is a uniform core-shell micellar assembly of polymer around the biocompatible metallic core. Doxorubicin and methotrexate are loaded within the architecture as the model therapeutic module. The drugs are linked through pH and enzyme sensitive bonds. The complete nano-architecture and linkages are characterized by electron microscopy, NMR and Photon Correlation Spectroscopy. The drug release response has been optimized with different cell line in vitro. The model suggest that change/increase in temperature, reduction of pH and the redox enzymatic activities are increased at the localized inflammatory sites, can be addressed by the developed module and the drug will be released at the inflammation sites only due to their specific linkage to the module. Again we have explored order–disorder micellar structures dependent T1 & T2 MRI properties of the module. This results indicate that the fabricated module can also be useful not only probing the inflammation site non invasively through MRI but also will give us idea on the extent of release of drugs at the inflammation sites. The outcomes of these results elucidate the potential of this fabricated nano-architecture for smart theranostics through physicochemical and microenvironment feature based drug delivery, site-specific therapy, real-time probing and non-invasive monitoring of the drug action course for personalized therapy.

     

  • 195.
    Pavlou, A
    et al.
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; .
    Turner, APF
    Cranfield University, UK.
    Magan, N
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; .
    Recognition of anaerobic bacterial isolates in vitro using electronic nose technology2002In: Letters in Applied Microbiology, ISSN 0266-8254, E-ISSN 1472-765X, Vol. 35, no 5, p. 366-369Article in journal (Refereed)
    Abstract [en]

    Aims: Use of an electronic nose (e.nose) system to differentiation between anaerobic bacteria grown in vitro on agar media. Methods and Results: Cultures of Clostridium spp. (14 strains) and Bacteroides fragilis (12 strains) were grown on blood agar plates and incubated in sampling bags for 30 min before head space analysis of the volatiles. Qualitative analyses of the volatile production patterns was carried out using an e.nose system with 14 conducting polymer sensors. Using data analysis techniques such as principal components analysis (PCA), genetic algorithms and neural networks it was possible to differentiate between agar blanks and individual species which accounted for all the data. A total of eight unknowns were correctly discriminated into the bacterial groups. Conclusions: This is the first report of in vitro complex volatile pattern recognition and differentiation of anaerobic pathogens. Significance and Impact of the Study: These results suggest the potential for application of e.nose technology in early diagnosis of microbial pathogens of medical importance.

  • 196.
    Pavlou, AK
    et al.
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; Gloucestershire Royal Hospital, Publ Hlth Lab Serv, Gloucester GL1 3NN, England; .
    Magan, N
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; Gloucestershire Royal Hospital, Publ Hlth Lab Serv, Gloucester GL1 3NN, England; .
    McNulty, C
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; Gloucestershire Royal Hospital, Publ Hlth Lab Serv, Gloucester GL1 3NN, England; .
    Jones, JM
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; Gloucestershire Royal Hospital, Publ Hlth Lab Serv, Gloucester GL1 3NN, England; .
    Sharp, D
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; Gloucestershire Royal Hospital, Publ Hlth Lab Serv, Gloucester GL1 3NN, England; .
    Brown, J
    Cranfield University, Institute Biosci and Technology, Silsoe MK45 4DT, Beds, England; Gloucestershire Royal Hospital, Publ Hlth Lab Serv, Gloucester GL1 3NN, England; .
    Turner, APF
    Cranfield University, UK.
    Use of an electronic nose system for diagnoses of urinary tract infections2002In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 17, no 10, p. 893-899Article in journal (Refereed)
    Abstract [en]

    The use of volatile production patterns produced by bacterial contaminants in urine samples were examined using electronic nose technology. In two experiments 25 and 45 samples from patients were analysed for specific bacterial contaminants using agar culture techniques and the major UTI bacterial species identified. These samples were also analysed by incubation in a volatile generation test tube system for 4-5 h. The volatile production patterns were then analysed using an electronic nose system with 14 conducting polymer sensors. In the first experiment analysis of the data using a neural network (NN) enabled identification of all but one of the samples correctly when compared to the culture information. Four groups could be distinguished, i.e. normal urine, Escherichia coli infected, Proteus spp. and Staphylococcus spp. In the second experiment it was again possible to use NN systems to examine the volatile production patterns and identify 18 of 19 unknown UTI cases. Only one normal patient sample was mis-identified as an E coli infected sample. Discriminant function analysis also differentiated between normal urine samples, that infected with E coli and with Staphylococcus spp. This study has shown the potential for early detection of microbial contaminants in urine samples using electronic nose technology for the first time. These findings will have implications for the development of rapid systems for use in clinical practice. (C) 2002 Elsevier Science B.V. All rights reserved.

  • 197.
    Pavlou, AK
    et al.
    Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; Gloucestershire Royal Hospital, PHLS and Gastroenterol Unit, Gloucester GL1 3NN, England; .
    Magan, N
    Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; Gloucestershire Royal Hospital, PHLS and Gastroenterol Unit, Gloucester GL1 3NN, England; .
    Sharp, D
    Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; Gloucestershire Royal Hospital, PHLS and Gastroenterol Unit, Gloucester GL1 3NN, England; .
    Brown, J
    Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; Gloucestershire Royal Hospital, PHLS and Gastroenterol Unit, Gloucester GL1 3NN, England; .
    Barr, H
    Cranfield University, Cranfield Biotechnol Centre, Cranfield MK43 0AL, Beds, England; Gloucestershire Royal Hospital, PHLS and Gastroenterol Unit, Gloucester GL1 3NN, England; .
    Turner, APF
    Cranfield University, UK.
    An intelligent rapid odour recognition model in discrimination of Helicobacter pylori and other gastroesophageal isolates in vitro2000In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 15, no 08-jul, p. 333-342Article in journal (Refereed)
    Abstract [en]

    Two series of experiments are reported which result in the discrimination between Helicobacter pylori and other bacterial gastroesophageal isolates using a newly developed odour generating system, an electronic nose and a hybrid intelligent odour recognition system. In the first series of experiments, after 5 h of growth (37 degreesC), 53 volatile sniffs were collected over the headspace of complex broth cultures of the following clinical isolates: Staphylococcus aureus, Klebsiella sp., H. pylori, Enterococcus faecalis (10(7) ml(-1)), Mixed infection (Proteus mirabilis, Escherichia coli, and E. faecalis 3 x 10(6) mi each) and sterile cultures. Fifty-six normalised variables were extracted from 14 conductive polymer sensor responses and analysed by a 3-layer back propagation neural network (NN). The NN prediction rate achieved was 98% and the test data (37.7% of all data) was recognised correctly. Successful clustering of bacterial classes was also achieved by discriminant analysis (DA) of a normalised subset of sensor data. Cross-validation identified correctly seven unknown samples. In the second series of experiments after 150 min of microaerobic growth at 37 degreesC, 24 volatile samples were collected over the headspace of H. pylori cultures in enriched (HPP) and normal (HP) media and 11 samples over sterile (N) cultures. Forty-eight sensor parameters were extracted from 12 sensor responses and analysed by a 3-layer NN previously optimised by a genetic algorithm (GA). GA-NN analysis achieved a 94% prediction rate or unknown data. Additionally the genetically selected 16 input neurones were used to perform DA-cross validation that showed a clear clustering of three groups and reclassified correctly nine sniffs. It is concluded that the most important factors that govern the performance of an intelligent bacterial odour detection system are: (a) an odour generation mechanism, (b) a rapid odour delivery system similar to the mammalian olfactory system, (c) a gas sensor array of high reproducibility and (d) a hybrid intelligent model (expert system) which will enable the parallel use of GA-NNs and multivariate techniques. (C) 1999 Elsevier Science S.A. All rights reserved.

  • 198.
    Pavlou, AK
    et al.
    Cranfield University, Postgrad Med Sch, Bedford MK43 0AL, England; Cranfield University, Institute Biosci and Technology, Silsoe, Beds, England; .
    Turner, APF
    Cranfield University, UK.
    Sniffing out the truth: Clinical diagnosis using the electronic nose2000In: Clinical Chemistry and Laboratory Medicine, ISSN 1434-6621, E-ISSN 1437-4331, Vol. 38, no 2, p. 99-112Article in journal (Refereed)
    Abstract [en]

    Recently the use of smell in clinical diagnosis has been rediscovered due to major advances in odour sensing technology and artificial intelligence (AI). It was well known in the past that a number of infectious or metabolic diseases could liberate specific odours characteristic of the disease stage. Later chromatographic techniques identified an enormous number of volatiles in human clinical specimens that might serve as potential disease markers. "Artificial nose" technology has been employed in several areas of medical diagnosis, including rapid detection of tuberculosis (TB), Helicobacter pylori (HP) and urinary tract infections (UTI). Preliminary results have demonstrated the possibility of identifying and characterising microbial pathogens in clinical specimens. A hybrid intelligent model of four interdependent "tools", odour generation "kits", rapid volatile delivery and recovery systems, consistent low drift sensor performance and a hybrid intelligent system of parallel neural networks (NN) and expert systems, have been applied in gastric, pulmonary and urine diagnosis. Initial clinical tests have shown that it may be possible in the near future to use electronic nose technology not only for the rapid detection of diseases such as peptic ulceration, UTI, and TB but also for the continuous dynamic monitoring of disease stages. Major advances in information and gas sensor technology could enhance the diagnostic power of future bio-electronic noses and facilitate global surveillance models of disease control and management.

  • 199.
    Pavlou, Alexandros K.
    et al.
    Institute of BioScience and Technology, Cranfield University, Bedfordshire, UK.
    Magan, Naresh
    Institute of BioScience and Technology, Cranfield University, Bedfordshire, UK.
    Jones, Jeff Meecham
    Public Health Laboratory Service, Gloucestershire Royal Hospital, Gloucester, UK.
    Brown, Jonathan
    Institute of BioScience and Technology, Cranfield University, Bedfordshire, UK.
    Klatser, Paul
    KIT Biomedical Research, Royal Tropical Institute, Amsterdam, The Netherlands.
    Turner, Anthony P.F.
    Cranfield University, UK.
    Detection of Mycobacterium tuberculosis (TB) in vitro and in situ using an electronic nose in combination with a neural network system2004In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 20, no 3, p. 538-544Article in journal (Refereed)
    Abstract [en]

    The use of volatile production patterns produced by Mycobacterium tuberculosis and associated bacterial infections from sputum samples were examined in vitro and in situ using an electronic nose based on a 14 sensor conducting polymer array. In vitro, it was possible to successfully discriminate between M. tuberculosis (TB) and control media, and between M. tuberculosis and M. avium, M. scrofulaceum and Pseudomonas aeruginosa cultures in the stationary phase after 5-6 h incubation at 37degreesC based on 35 samples. Using neural network (NN) analysis and cross-validation it was possible to successfully identify 100% of the TB cultures from others. A second in vitro study with 61 samples all four groups were successfully discriminated with 14 of 15 unknowns within each of the four groups successfully identified using cross-validation and discriminant function analysis. Subsequently, lipase enzymes were added to 46 sputum samples directly obtained from patients and the head space analysed. Parallel measurements of bacterial contamination were also carried out for confirmation using agar media. NN analysis was carried out using some of the samples as a training set. Based on the NN and genetic algorithms of up to 10 generations it was possible to successfully cross-validate 9 of 10 unknown samples. PCA was able to discriminate between TB infection alone, the controls, M. avium, P. aeruginosa and a mixed infection. These findings will have significant implications for the development of rapid qualitative systems for screening of patient samples and clinical diagnosis of tuberculosis.

  • 200.
    Perez, FG
    et al.
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; .
    Mascini, M
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; .
    Tothill, IE
    University Florence, Dipartimento Sanita Pubbl Epidemiol and Chim Analit, Florence, Italy; .
    Turner, APF
    Cranfield University, UK.
    Immunomagnetic separation with mediated flow injection analysis amperometric detection of viable Escherichia coli O1571998In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 70, no 11, p. 2380-2386Article in journal (Refereed)
    Abstract [en]

    The coupling of an immunological separation (using immunomagnetic beads) with amperometric now injection analysis detection of viable bacteria is presented. Using a solution containing Escherichia coli O157, the electrochemical response with two different mediators [potassium hexacyanoferrate(III) and 2,6-dichlorophenolindophenol] was evaluated in the FIA system. Antibody-derivatized Dynabeads were used to selectively separate E. coli O157 from a matrix The kinetics and the capacity parameters regarding the attachment of bacteria to the immunobeads were studied. The immunomagnetic separation was then used in conjunction with electrochemical detection to measure the concentration of viable bacteria. A calibration curve of colony-forming units (du) against electrochemical response was obtained. The detection limit for this rapid microbiological method was 10(5) cfu mL(-1), and the complete assay was performed in 2 h. Some advantages over ELISA methods are the direct detection of viable cells (and not total bacterial load) and the need for only one antibody (not enzyme-labeled), thus making the assay faster (only one washing step is necessary) and less expensive.

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