Attachment and Detection of Biofouling Yeast Cells Using Biofunctionalized Resonant Sensor Modality

This research addresses fuel biocontaminant sensing using resonant photonic gratings. The fundamental photonic resonance physics enables compact, economic sensors that provide a rapid, quantitative, and effective modality for detecting and monitoring biochemical bindings. Thus, we present resonant sensors and attendant surface chemistry targeting yeast cells as representative biofouling agents. We apply biorecognition elements (BREs) to functionalize the dielectric grating surface (TiO2) to produce a sensitive, quantitative wavelength shift-based assay for detecting Yarrowia yeast cells. Concanavalin A (Con A) is used as a BRE consisting of carbohydrate-binding proteins binding to ligands on the yeast cell surface. Corresponding resonance wavelength shifts are measured relative to concentration expressed in log10 [C] where C represents the concentration of cells in solution. The assay is shown to be highly specific for detecting Yarrowia cells in various concentrations. The experimental limit of detection (LOD) of the assay is 1.92 for yeast cells in culture media and 1.22 for cells in phosphate buffer saline (PBS). The comparisons of the various functionalization methods show that (3-aminopropyl)triethoxysilane (APTES) with glutardialdehyde (GA) and Con A protocol provides optimal detection of cells in PBS.