This Small Business Innovation Research (SBIR) Phase I research uses electrospray ionization as a deposition method for rapid and reproducible generation of advanced biosensor substrates. Deposition of bioactive surfaces for immunoassay based sensing elements is usually based on a wet-chemical approach. Unfortunately, the preparation and covalent linkage steps in such wet-chemical approaches can take several days, and are prone to inconsistency due to the elaborate multi-step processes. Electrospray ionization offers the opportunity for a new approach to this problem by direct spray deposition. The ionization process enables direct beam focusing, leading naturally to patterning and array based sensing elements. Electrospray deposition not only promises better control over the assay quality, but also enables production schemes such as continuous roll-to-roll processing. Since the process leverages directed deposition rather than diffusion kinetics from a liquid overlayer, process times of minutes are possible. Preliminary results for detection of pathogenic E. coli O157:H7 bacteria using electrospray deposited immunoassay substrates have demonstrated sensitivities similar to wet chemically prepared samples, and further optimization will be performed. This research will lead to improved methods for production of biosensors that delivers higher quality at a reduced cost to improve the overall utility of biosensors to the country.
