Live Tracking Biofunctionalization and Label-Free Protein Detection Performed by a Nanophotonic Biosensor

A label-free biosensor based on silicon-on-insulator (SOI) photonic bandgap (PBG) structures is performed for specific protein detection. First, the SOI sensing surface is functionalized using triethoxyvinylsilane (TEVS) organosilane. Then, a UV light photocatalyzed immobilization of polyclonal half anti-bovine serum albumin (haBSA) antibodies is performed. Finally, a direct detection of target BSA antigen is carried out. Both the immobilization and the detection steps are monitored by making a continuous tracking of the PBG edge shift. In order to confirm the recognition of the antigen by the immobilized antibody, a fluorophore-labelled secondary antibody was flowed at the end of the experiment in order to perform a confirmation fluorescence test after the photonic detection.