Total internal reflection ellipsometry as a label-free assessment method for optimization of the reactive surface of bioassay devices based on a functionalized cycloolefin polymer

• Published in: Analytical & bioanalytical chemistry (Print) 2010-11, Vol.398 (5), p.1927-1936
• Main Authors: Le, Nam Cao Hoai, Gubala, Vladimir, Gandhiraman, Ram P, Coyle, Conor, Daniels, Stephen, Williams, David E
• Format: Article
• Language: English
• Subjects: Analysis; Analytical Chemistry; Applied sciences; Assessments; Biochemistry; Biological and medical sciences; Biomolecules; Biosensors; Biotechnology; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chorionic Gonadotropin - chemistry; Cycloolefin polymer; Cycloparaffins - chemistry; Deoxyribonucleic acid; Detectors; DNA; Ellipsometry; Exact sciences and technology; Food Science; Fundamental and applied biological sciences. Psychology; General, instrumentation; Global environmental pollution; Humans; Immunoassay; Immunoassay - instrumentation; Immunoassay - methods; immunoassays; Laboratory Medicine; Mathematical models; Methods; Methods. Procedures. Technologies; Microfluidics; Microfluidics - instrumentation; Microfluidics - methods; Miscellaneous; Molecular Structure; Monitoring/Environmental Analysis; nucleic acid hybridization; Original Paper; Placental hormones; Plasma-enhanced chemical vapour deposition; Pollution; Polymer industry; Polymers; Polymers - chemistry; Reflection; Staining and Labeling; Surface chemistry; Surface Properties; Technology application; Tires; Total internal reflection ellipsometry; Various methods and equipments
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-010-4099-4

We report a label-free optical detection technique, called total internal reflection ellipsometry (TIRE), which can be applied to study the interactions between biomolecules and a functionalized polymer surface. Zeonor (ZR), a cycloolefin polymer with low autofluorescence, high optical transmittance and excellent chemical resistance, is a highly suitable material for optical biosensor platforms owing to the ease of fabrication. It can also be modified with a range of reactive chemical groups for surface functionalization. We demonstrate the applications of TIRE in monitoring DNA hybridization assays and human chorionic gonadotrophin sandwich immunoassays on the ZR surface functionalized with carboxyl groups. The Ψ and Δ spectra obtained after the binding of each layer of analyte have been fitted to a four-layer ellipsometric model to quantitatively determine the amount of analytes bound specifically to the functionalized ZR surface. Our proposed TIRE technique with its very low analyte consumption and its microfluidic array format could be a useful tool for evaluating several crucial parameters in immunoassays, DNA interactions, adsorption of biomolecules to solid surfaces, or assessment of the reactivity of a functionalized polymer surface towards a specific analyte. [graphic removed]