Characterizing the bio-functionalization of gold surface with total internal reflection fluorescence (TIRF) microscopy

Abstract

Quality of bioactive surface is crucial for achieving the required sensitivity and selectivity of biosensing systems. Numerous methods are available for the characterization of metal-coated surfaces, but only a few to test the efficacy of biomaterial immobilization and the level of non-specific binding. Herewith we propose to use total internal reflection fluorescence (TIRF) microscopy for the characterization of the surface analyte recognition capacity. Biomolecules were bound onto titanium/gold covered glass using three different self-assembled monolayers (SAM). The surfaces with attached antibodies were evaluated using the specific binding of fluorophore-labeled secondary antibodies and visualized with TIRF. Among studied SAMs, aminothiol layers with glutaraldehyde coupling demonstrated high binding capacity along with excellent homogeneity indicating their suitability for applications in biosensors.