title: Combining an optical resonance biosensor with enzyme activity kinetics to understand protein adsorption and denaturation.
abstract: Understanding protein adsorption and resultant conformation changes on modified and unmodified silicon dioxide surfaces is a subject of keen interest in biosensors, microfluidic systems and for medical diagnostics. However, it has been proven difficult to investigate the kinetics of the adsorption process on these surfaces as well as understand the topic of the denaturation of proteins and its effect on enzyme activity. A highly sensitive optical whispering gallery mode (WGM) resonator was used to study a catalytic enzyme's adsorption processes on different silane modified glass substrates (plain glass control, DETA, 13 F, and SiPEG). The WGM sensor was able to obtain high resolution kinetic data of glucose oxidase (GO) adsorption with sensitivity of adsorption better than that possible with SPR. The kinetic data, in combination with a functional assay of the enzyme activity, was used to test hypotheses on adsorption mechanisms. By fitting numerical models to the WGM sensograms for protein adsorption, and by confirming numerical predictions of enzyme activity in a separate assay, we were able to identify mechanisms for GO adsorption on different alkylsilanes and infer information about the adsorption of protein on nanostructured surfaces.
authors.affiliation: Nanoscience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA.
authors.forename: Kerry A
authors.initials: KA
authors.lastname: Wilson
authors.affiliation: Nanoscience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Finch
authors.affiliation: Nanoscience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA.
authors.forename: Phillip
authors.initials: P
authors.lastname: Anderson
authors.affiliation: The Wyss & Rowland Institutes, Harvard University, 100 Edwin H. Land Blvd, Cambridge, MA 02142, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Vollmer
authors.affiliation: Nanoscience Technology Center, University of Central Florida, 12424 Research Parkway, Orlando, FL 32826, USA. Electronic address: jhickman@mail.ucf.edu.
authors.forename: James J
authors.initials: JJ
authors.lastname: Hickman
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation*; D003198:Computer Simulation; D004789:Enzyme Activation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005949:Glucose Oxidase / Q000737:chemistry* / Q000648:ultrastructure*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008956:Models, Chemical; D008958:Models, Molecular; D011489:Protein Denaturation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D018511:Systems Integration
chemical_list: D005949:Glucose Oxidase
keywords: Biosensor; Modeling; Nanobiotechnology; Protein adsorption; Self-assembled monolayer; Surface modification