This Small Business Innovation Research (SBIR) Phase I project concerns the development of an optical fiber biosensor platform that achieves exceptionally high sensitivity through use of a nanoscale, high refractive index, self-assembled polymer coating on the cladding surface. A rapid, specific, and sensitive detection system for methicilin-resistant Staphylococcus aureus (MRSA) and other biological analytes will be developed that is inexpensive, portable and rugged. The key innovation is the combination of ionic self-assembled multilayers (ISAMs), which allow deposition of a variety of materials including polymers and nanoparticles into multiple layers each just a nanometer thick, with turnaround point long-period gratings (TAP-LPGs), which have strong, broadband attenuation peaks that are highly sensitive to changes on the exterior of the optical fiber cladding. The TAP-LPG provides a highly sensitive, robust, inexpensive biosensor platform where the presence of target materials is detected simply by changes in the transmitted intensity at a particular wavelength, while the ISAM film amplifies the sensitivity by providing a high refractive index, high surface area, nanoscale coating on the cladding that can be readily coupled to a vast array of receptor molecules such as antibodies. The broader impact / commercial potential of this project includes the creation of a novel, inexpensive, highly sensitive, rugged, portable biosensor platform that will allow early and rapid diagnosis of MRSA infection. The broad antibiotic resistance of MRSA makes it a particularly important target for rapid diagnosis so that the proper treatment can be promptly administered. MRSA is responsible for thousands of deaths annually in the United States and extended hospital visits for >100,000 patients per year. Further, the proposed novel biological diagnostic platform combines the precision of photonic sensing and nanotechnology with a versatile affinity binding system to make ultrasensitive measurements of biomarkers for a vast array of additional important targets for medical diagnostics, drug discovery, and environmental monitoring. In addition, the small size and low cost of the system makes it also applicable to remote and impoverished areas of the globe. Furthermore, the project will provide fundamental information on the optical properties of nanoscale self-assembled films and their interactions with biological molecules and organisms
