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Andersson, Olof
Alternative names
Publications (10 of 27) Show all publications
Tai, F.-i., Sterner, O., Andersson, O., Ekblad, T. & Ederth, T. (2019). Interaction Forces on Polyampholytic Hydrogel Gradient Surfaces. ACS Omega, 4(3), 5670-5681
Open this publication in new window or tab >>Interaction Forces on Polyampholytic Hydrogel Gradient Surfaces
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2019 (English)In: ACS Omega, ISSN 2470-1343, Vol. 4, no 3, p. 5670-5681Article in journal (Refereed) Published
Abstract [en]

Rational design and informed development of nontoxic antifouling coatings requires a thorough understanding of the interactions between surfaces and fouling species. With more complex antifouling materials, such as composites or zwitterionic polymers, there follows also a need for better characterization of the materials as such. To further the understanding of the antifouling properties of charge-balanced polymers, we explore the properties of layered polyelectrolytes and their interactions with charged surfaces. These polymers were prepared via self-initiated photografting and photopolymerization (SIPGP); on top of a uniform bottom layer of anionic poly(methacrylic acid) (PMAA), a cationic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) thickness gradient was formed. Infrared microscopy and imaging spectroscopic ellipsometry were used to characterize chemical composition and swelling of the combined layer. Direct force measurements by colloidal probe atomic force microscopy were performed to investigate the forces between the polymer gradients and charged probes. The swelling of PMAA and PDMAEMA are very different, with steric and electrostatic forces varying in a nontrivial manner along the gradient. The gradients can be tuned to form a protein-resistant charge-neutral region, and we demonstrate that this region, where both electrostatic and steric forces are small, is highly compressed and the origin of the protein resistance of this region is most likely an effect of strong hydration of charged residues at the surface, rather than swelling or bulk hydration of the polymer. In the highly swollen regions far from charge-neutrality, steric forces dominate the interactions between the probe and the polymer. In these regions, the SIPGP polymer has qualitative similarities with brushes, but we were unable to quantitatively describe the polymer as a brush, supporting previous data suggesting that these polymers are cross-linked.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:liu:diva-156495 (URN)10.1021/acsomega.9b00339 (DOI)000462921900124 ()31459721 (PubMedID)2-s2.0-85063358089 (Scopus ID)
Note

Funding agencies: European Commissions Sixth Framework Program Integrated Project AMBIO (Advanced Nanostructured Surfaces for the Control of Biofouling) [NMP-CT-2005-011827]; European Communitys Seventh Framework Program [237997]; Swedish Government Strategic Research Area

Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2019-09-09Bibliographically approved
Tai, F.-I., Sterner, O., Andersson, O., Ekblad, T. & Ederth, T. (2015). pH-control of the protein resistance of hydrogel gradient films. In: : . Paper presented at 79th Prague Meeting on Macromolecules, Prague, Czech, 28 June - 2 July 2015.
Open this publication in new window or tab >>pH-control of the protein resistance of hydrogel gradient films
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2015 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-122697 (URN)
Conference
79th Prague Meeting on Macromolecules, Prague, Czech, 28 June - 2 July 2015
Available from: 2015-11-16 Created: 2015-11-16 Last updated: 2018-09-26Bibliographically approved
Lundgren, A., Hulander, M., Brorsson, J., Hermansson, M., Elwing, H., Andersson, O., . . . Berglin, M. (2014). Gold-Nanoparticle-Assisted Self-Assembly of Chemical Gradients with Tunable Sub-50 nm Molecular Domains. Particle & particle systems characterization, 31(2), 209-218
Open this publication in new window or tab >>Gold-Nanoparticle-Assisted Self-Assembly of Chemical Gradients with Tunable Sub-50 nm Molecular Domains
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2014 (English)In: Particle & particle systems characterization, ISSN 0934-0866, E-ISSN 1521-4117, Vol. 31, no 2, p. 209-218Article in journal (Refereed) Published
Abstract [en]

A simple and efficient principle for nanopatterning with wide applicability in the sub-50 nanometer regime is chemisorption of nanoparticles; at homogeneous substrates, particles carrying surface charge may spontaneously self-organize due to the electrostatic repulsion between adjacent particles. Guided by this principle, a method is presented to design, self-assemble, and chemically functionalize gradient nanopatterns where the size of molecular domains can be tuned to match the level corresponding to single protein binding events. To modulate the binding of negatively charged gold nanoparticles both locally (less than100 nm) and globally (greater than100 m) onto a single modified gold substrate, ion diffusion is used to achieve spatial control of the particles mutual electrostatic interactions. By subsequent tailoring of different molecules to surface-immobilized particles and the void areas surrounding them, nanopatterns are obtained with variable chemical domains along the gradient surface. Fimbriated Escherichia coli bacteria are bound to gradient nanopatterns with similar molecular composition and macroscopic contact angle, but different sizes of nanoscopic presentation of adhesive (hydrophobic) and repellent poly(ethylene) glycol (PEG) domains. It is shown that small hydrophobic domains, similar in size to the diameter of the bacterial fimbriae, supported firmly attached bacteria resembling catch-bond binding, whereas a high number of loosely adhered bacteria are observed on larger hydrophobic domains.

Place, publisher, year, edition, pages
Wiley-VCH Verlag, 2014
Keywords
bacterial adhesion; chemical gradients; gold nanoparticles; imaging surface plasmon resonance; protein nanopatterns
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-105760 (URN)10.1002/ppsc.201300154 (DOI)000331904500005 ()
Available from: 2014-04-07 Created: 2014-04-04 Last updated: 2017-12-05
Tai, F.-i., Sterner, O., Andersson, O., Ekblad, T. & Ederth, T. (2014). pH-control of the protein resistance of thin hydrogel gradient films. Soft Matter, 10(32), 5955-5964
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2014 (English)In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 10, no 32, p. 5955-5964Article in journal (Refereed) Published
Abstract [en]

We report on the preparation and characterization of thin polyampholytic hydrogel gradient films permitting pH-controlled protein resistance via the regulation of surface charges. The hydrogel gradients are composed of cationic poly(2-aminoethyl methacrylate hydrochloride) (PAEMA), and anionic poly(2-carboxyethyl acrylate) (PCEA) layers, which are fabricated by self-initiated photografting and photopolymerization (SIPGP). Using a two-step UV exposure procedure, a polymer thickness gradient of one component is formed on top of a uniform layer of the oppositely charged polymer. The swelling of the gradient films in water and buffers at different pH were characterized by imaging spectroscopic ellipsometry. The surface charge distribution and steric interactions with the hydrogel gradients were recorded by direct force measurement with colloidal-probe atomic force microscopy. We demonstrate that formation of a charged polymer thickness gradient on top of a uniform layer of opposite charge can result in a region of charge-neutrality. This charge-neutral region is highly resistant to non-specific adsorption of proteins, and its location along the gradient can be controlled via the pH of the surrounding buffer. The pH-controlled protein adsorption and desorption was monitored in real-time by imaging surface plasmon resonance, while the corresponding redistribution of surface charge was confirmed by direct force measurements.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2014
National Category
Physical Sciences
Identifiers
urn:nbn:se:liu:diva-110502 (URN)10.1039/c4sm00833b (DOI)000340474400011 ()24987939 (PubMedID)
Note

Funding Agencies|European Commission [NMP-CT-2005-011827]; European Community [237997]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Available from: 2014-09-12 Created: 2014-09-12 Last updated: 2019-04-24
Aldred, N., Ekblad, T., Andersson, O., Liedberg, B. & Clare, A. S. (2011). Real-Time Quantification of Microscale Bioadhesion Events In situ Using Imaging Surface Plasmon Resonance (iSPR). ACS Applied Materials and Interfaces, 3(6), 2085-2091
Open this publication in new window or tab >>Real-Time Quantification of Microscale Bioadhesion Events In situ Using Imaging Surface Plasmon Resonance (iSPR)
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2011 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 3, no 6, p. 2085-2091Article in journal (Refereed) Published
Abstract [en]

From macro- to nanoscales, adhesion phenomena are all-pervasive in nature yet remain poorly understood. In recent years, studies of biological adhesion mechanisms, terrestrial and marine, have provided inspiration for "biomimetic" adhesion strategies and important insights for the development of fouling-resistant materials. Although the focus of most contemporary bioadhesion research is on large organisms such as marine mussels, insects and geckos, adhesion events on the micro/nanoscale are critical to our understanding of important underlying mechanisms. Observing and quantifying adhesion at this scale is particularly relevant for the development of biomedical implants and in the prevention of marine biofouling. However, such characterization has so far been restricted by insufficient quantities of material for biochemical analysis and the limitations of contemporary imaging techniques. Here, we introduce a recently developed optical method that allows precise determination of adhesive deposition by microscale organisms in situ and in real time; a capability not before demonstrated. In this extended study we used the cypris larvae of barnacles and a combination of conventional and imaging surface plasmon resonance techniques to observe and quantify adhesive deposition onto a range of model surfaces (CH(3)-, COOH-, NH(3)-, and mPEG-terminated SAMs and a PEGMA/HEMA hydrogel). We then correlated this deposition to passive adsorption of a putatively adhesive protein from barnacles. In this way, we were able to rank surfaces in order of effectiveness for preventing barnacle cyprid exploration and demonstrate the importance of observing the natural process of adhesion, rather than predicting surface effects from a model system. As well as contributing fundamentally to the knowledge on the adhesion and adhesives of barnacle larvae, a potential target for future biomimetic glues, this method also provides a versatile technique for laboratory testing of fouling-resistant chemistries.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2011
Keywords
imaging SPR; barnacle cyprid; footprints; biological adhesion; biofouling
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-69884 (URN)10.1021/am2003075 (DOI)000291781800043 ()
Available from: 2011-08-09 Created: 2011-08-08 Last updated: 2017-12-08
Wigenius, J., Magnusson, K., Björk, P., Andersson, O. & Inganäs, O. (2010). DNA Chips with Conjugated Polyelectrolytes in Resonance Energy Transfer Mode. LANGMUIR, 26(5), 3753-3759
Open this publication in new window or tab >>DNA Chips with Conjugated Polyelectrolytes in Resonance Energy Transfer Mode
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2010 (English)In: LANGMUIR, ISSN 0743-7463, Vol. 26, no 5, p. 3753-3759Article in journal (Refereed) Published
Abstract [en]

We show how to use well-defined conjugated polyelectrolytes (CPEs) combined With Surface energy patterning to Fabricate DNA Chips utilizing A fluorescence signal amplification. Cholesterol-modified DNA strands in complex with it CPE are adsorbed to a surface energy pattern, formed by printing with soft elastomer stamps. Hybridization of the surface bound DNA strands with it short complementary strand from Solution is monitored using both fluorescence microscopy and imaging surface plasmon resonance. The CPEs act as antennas, enhancing resonance energy transfer to the dye-labeled DNA when complementary hybridization of the double strand occurs.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-54255 (URN)10.1021/la903101v (DOI)000274636900113 ()
Available from: 2010-03-05 Created: 2010-03-05 Last updated: 2015-05-29
Ekblad, T., Faxälv, L., Andersson, O., Wallmark, N., Larsson (Kaiser), A., Lindahl, T. L. & Liedberg, B. (2010). Patterned Hydrogels for Controlled Platelet Adhesion from Whole Blood and Plasma. Advanced Functional Materials, 20(15), 2396-2403
Open this publication in new window or tab >>Patterned Hydrogels for Controlled Platelet Adhesion from Whole Blood and Plasma
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2010 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 20, no 15, p. 2396-2403Article in journal (Refereed) Published
Abstract [en]

This work describes the preparation and properties of hydrogel surface chemistries enabling controlled and well-defined cell adhesion. The hydrogels may be prepared directly on plastic substrates, such as polystyrene slides or dishes, using a quick and experimentally simple photopolymerization process, compatible with photolithographic and microfluidic patterning methods. The intended application for these materials is as substrates for diagnostic cell adhesion assays, particularly for the analysis of human platelet function. The adsorption of fibrinogen and other platelet promoting molecules is shown to be completely inhibited by the hydrogel, provided that the film thickness is sufficient (>5 nm). This allows the hydrogel to be used as a matrix for presenting selected bioactive ligands without risking interference from nonspecifically adsorbed platelet adhesion factors, even in undiluted whole blood and blood plasma. This concept is demonstrated by preparing patterns of proteins on hydrogel surfaces, resulting in highly controlled platelet adhesion. Further insights into the protein immobilization and platelet adhesion processes are provided by studies using imaging surface plasmon resonance. The hydrogel surfaces used in this work appear to provide an ideal platform for cell adhesion studies of platelets, and potentially also for other cell types.

Place, publisher, year, edition, pages
John Wiley & Sons, 2010
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-54301 (URN)10.1002/adfm.201000083 (DOI)000281058900003 ()
Available from: 2010-03-08 Created: 2010-03-08 Last updated: 2017-12-12
Andersson, O., Nikkinen, H., Kanmert, D. & Enander, K. (2009). A multiple-ligand approach to extending the dynamic range of analyte quantification in protein microarrays. Biosensors and bioelectronics, 24(8), 2458-2464
Open this publication in new window or tab >>A multiple-ligand approach to extending the dynamic range of analyte quantification in protein microarrays
2009 (English)In: Biosensors and bioelectronics, ISSN 0956-5663, Vol. 24, no 8, p. 2458-2464Article in journal (Refereed) Published
Abstract [en]

This work describes a concept for extending the dynamic range of quantification in an affinity biosensor assay by using a set of ligands with different affinities toward a common analyte. For a demonstration of the principle, three synthetic, biotinylated polypeptides capable of binding a model protein analyte with different affinities (10-9 M ≤ Kd ≤ 10-7 M) were immobilized in a microarray format on a gold slide covered with an oligo(ethylene glycol)-containing alkane thiolate self-assembled monolayer. For controllable immobilization, coupling was mediated by the biotinneutravidin interaction. A five-element affinity array, comprising single-peptide spots as well as spots where peptides were immobilized in mixtures, was realized by means of piezodispensation. Imaging surface plasmon resonance was used to study binding of the analyte to the different spots. The lower limit of quantification was ~3 nM and the corresponding upper limit was increased by more than an order of magnitude compared to if only the highest-affinity ligand would have been used. Affinity array sensors with multiple ligands for each analyte are particularly interesting for omitting dilution steps and providing highly accurate data in assays where several analytes such as disease biomarkers with extremely variable concentrations are quantified in parallel.

Keywords
Imaging surface plasmon resonance, Biosensor, Affinity microarray, Analyte quantification, Synthetic polypeptide
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-14922 (URN)10.1016/j.bios.2008.12.030 (DOI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2015-05-29
Andersson, O., Larsson (Kaiser), A., Ekblad, T. & Liedberg, B. (2009). Gradient Hydrogel Matrix for Microarray and Biosensor Applications: An Imaging SPR Study. Biomacromolecules, 10(1), 142-148
Open this publication in new window or tab >>Gradient Hydrogel Matrix for Microarray and Biosensor Applications: An Imaging SPR Study
2009 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, no 1, p. 142-148Article in journal (Refereed) Published
Abstract [en]

A biosensor matrix based on UV-initiated graft copolymerized poly(ethylene glycol) methacrylate and 2-hydroxyethyl methacrylate has been studied using imaging surface plasmon resonance (iSPR). By using a photo mask and a programmable shutter to vary the exposure time laterally, a gradient of matrix spots with physical thicknesses ranging from a few to tens of nanometers was generated. To maximize the dynamic range, imaging SPR was employed in wavelength interrogation mode. By finding the minimum in the reflectance spectra from each pixel of an image, SPR wavelength maps were constructed. The shift in SPR wavelength upon biospecific interaction was then measured both as a function of matrix thickness and composition. The performance of the matrix was evaluated in terms of immobilization of human serum albumin, biomolecular interaction with its antibody, and nonspecific binding of human fibrinogen. In addition, a low molecular weight interaction pair based on a synthetic polypeptide and calmodulin was also studied to explore the size selectivity of the hydrogel matrix. Our results show that the gradient matrix exhibits excellent properties for quick evaluation and screening of optimal hydrogel performance. The mixed hydrogel matrices display very low levels of nonspecific binding. It is also evident that the low molecular weight calmodulin is capable of freely diffusing and interacting throughout the entire hydrogel matrix, whereas the much larger albumin and its corresponding antibody, in particular, are partly/completely hindered from penetrating the interior of the matrix. This size-selectivity is attributed to a significant UV-initiated cross-linking or branching of the matrix during fabrication and/or protein mediated multipoint attachment during immobilization.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-16523 (URN)10.1021/bm801029b (DOI)
Available from: 2009-01-30 Created: 2009-01-30 Last updated: 2017-12-14
Ekblad, T., Andersson, O., Tai, F.-i., Ederth, T. & Liedberg , B. (2009). Lateral Control of Protein Adsorption on Charged Polymer Gradients. Langmuir, 25(6), 3755-3762
Open this publication in new window or tab >>Lateral Control of Protein Adsorption on Charged Polymer Gradients
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2009 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, no 6, p. 3755-3762Article in journal (Refereed) Published
Abstract [en]

This work describes the fabrication, characterization, and protein adsorption behavior of charged polymer gradients. The thin gradient films were fabricated by a two-step technique using UV-initiated free-radical polymerization in a reactor with a moving shutter. A homogeneous layer of cationic poly(2-aminoethyl methacrylate hydrochloride) was first formed, followed by a layer of oppositely charged poly(2-carboxyethyl acrylate) with a continuously increasing thickness. Adsorption from protein solutions as well as human blood plasma was investigated by imaging surface plasmon resonance and infrared microscopy. The results showed excessive protein adsorption in the areas where one of the polymers dominated the composition, while there was a clear minimum at an intermediate position of the gradient. The charge of the surface was estimated by direct force measurements and found to correlate well with the protein adsorption, showing the lowest net charge in the same area as the protein adsorption minimum. We therefore hypothesize that a combination of the charged polymers, in the right proportions, can result in a protein-resistant surface due to balanced charges.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-17501 (URN)10.1021/la803443d (DOI)
Available from: 2009-03-27 Created: 2009-03-27 Last updated: 2019-04-24
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