(306d) On-chip bio-sensor for microbial contamination

Quantification of microbial assay for possible food and water contamination, especially for long-duration space missions is critically important to understand potential risk to the crew members. In this study, on-chip biosensor was fabricated for rapid screening and quantification of microbial contamination. Low-k dielectric (SiO₂, Gr- doped SiO₂) porous thin-film layers were deposited on ITO by surface templating assisted sol-gel method. Gels were prepared with alkoxides dispersed in ethanol containing CTAC or pluronic123 by varying concentration of precursors and surfactant, and aging time. As spun thin-film substrates were subjected initially to soft-bake followed by annealing at 400^oC and characterized for porosity, pore size, and refractive index. Hydrophilic/ hydrophobic nature of the films were characterized by the contact angle measurements. Gr – SiO₂ porous layer was immobilized with the anti-microbial peptides (AMP) and specific binding ability of microbes was studied by the conductivity measurements. Fabrication and characterization of porous low-k(modified with Gr) thin-films, and results obtained with AMP binding and biosensing ability will be presented.