Phase 2 SBIR Final Report: An Ultra-Sensitive Optical Biosensor for Flood Safety

Abstract

Subject Terms Report Classification unclassified Classification of this page unclassified Classification of Abstract unclassified Limitation of Abstract UU Number of Pages 247i Phase II SBIR Final Report: An Ultra-Sensitive Optical Biosensor for Food Safety (Contract DAAD16-01-C-0001) Executive Summary. The further development of a unique interferometric based optical biosensor platform for the rapid unlabelled detection and identification of foodborne pathogens was carried out under Phase II SBIR contract DAAD16-01-C-0001 entitled: An Ultra-Sensitive Optical Biosensor for Food Safety. The potential in combining optical methods with biomolecular recognition techniques is the high signal gain derived from photonic amplification and thus high sensitivity, specificity, and rapid response time.This Phase II effort was focused on the development of the following innovations:• Microfluidic diffusional filtering of bacterial cells for high-throughput 'on-chip' purification of real-world samples prior to detection, • Biomolecular immobilization based on the application of thin self-assembled polyethylene oxide derived molecular films with for highly controlled positioning of receptor sites and the suppression of non-specific binding events, • Uigh resolution interferometric evanescent wave detection based on the modulation of polarization and the subsequent differencing of TE and TM modes for highly stable and self-compensated operation, and • The spatial manipulation of the cells within a microfluidic environment to steer the sample stream nearer to the receptors for increased probability of capture.The goal of the effort was the eventual development of a portable biosensing platform for the detection and identification of viable pathogenic microbes in foods at the level of 1 CFU/mL within a 30-minute period.The usual 24-month Phase II SBIR program was accelerated to hasten the commercialization of the technology, however the program was terminated at 18 months after both contract funding and SatCon cost-share had been expended, and no follow-on funding was attainable. The original proposal, written only four months into the Phase I effort, was modified to perform a bench-top level effort and not the fully miniaturized development originally proposed. Costsharing equivalent to the indirect program costs was borne by SatCon.Laboratory Development. The different sub-systems were developed, tested, and integrated to the extent possible. A summary of these efforts are provided below:• A 'doubly differential' interferometer, relying on the difference in evanescence response between modulating polarizations, was built. The transducer monitored changes in the speed of light caused by surface binding propagating through a single-mode waveguide. A first generation grating coupled waveguide was fabricated but was unusable due to poor light throughput. The design of the next generation waveguide was improved with the incorporation of 1 st order diffraction gratings. A commercial fabrication facility capable of doing the ...