Optimisation of glass surfaces for optical immunosensors.
The surfaces of glass sensor chips were modified with dextran to generate a layer protecting the sensor surface from unspecific protein binding and also serving as a matrix for covalent protein immobilisation. Dextran was coupled to the glass surface in different concentrations either covalently on amino-functionalised glass chips or via biotin-avidin binding. Unspecific binding of BSA was monitored with the grating coupler system, and was increasingly suppressed with increasing dextran concentrations. Using a solution with 100 mg/ml carboxymethylated dextran decreased the signals to approximately 2% of those obtained at an untreated glass chip. Antibodies were successfully immobilised in the dextran and binding to the corresponding Cy5-labelled antigen was repeatedly monitored using a fluorescence sensor system (total internal reflection fluorescence (TIRF)).
Akkoyun
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Gesellschaft für Biotechnologische Forschung mb H, Div. Biochemical Engineering, Mascheroder Weg 1, D-38124, Braunschweig, Germany. akkoyun@gmx.de
Bilitewski
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D000818:Animals; D000906:Antibodies; D001360:Avidin; D015374:Biosensing Techniques / Q000295:instrumentation*; D001710:Biotin; D002417:Cattle; D003911:Dextrans; D005453:Fluorescence; D005898:Glass; D055095:Optics and Photonics / Q000295:instrumentation; D011485:Protein Binding; D012710:Serum Albumin, Bovine; D013499:Surface Properties
D000906:Antibodies; D003911:Dextrans; D001360:Avidin; D012710:Serum Albumin, Bovine; D001710:Biotin