Polarization Metasurface Detection Device for Food Safety

Project Summary/Abstract For farm-to-fork testing for the entire food supply chain, Nanohmics proposes to develop its metasurface-based MetaDotTM bind-and-detect biosensor for portable, low-cost, rapid, highly sensitive multiplex screening of foodborne pathogens. Nanohmics’ MetaDot optical reader is designed to measure pathogen binding on a custom optical metasurface test chip coated with an array of bioreceptor regions (dots), each functionalized for direct covalent receptor binding using aminated antibodies or DNA aptamers. MetaDot will provide easy and highly accurate multiplex detection, identification, and quantification of foodborne pathogens. Each single-use functionalized biosensor chip is mounted in a custom cassette for precise insertion into the MetaDot reader. When the biosensor chip is exposed to the rinsate or solution under test, the reader probes the 36 dot regions simultaneously using polarized monochromatic light reflected by each dot as a function of the density of local pathogen binding. Phase II will demonstrate a simultaneous test for less than $3 for 36 dots, enough to cover the 31 major identified foodborne pathogens. The Phase II program will develop and test the MetaDot prototype:Research Aim 1 addresses low-cost multiplex functionalization using a microspotting robot.Research Aim 2 develops the reader.Research Aim 3 concentrates on reducing the cost of metasurface microfabrication. Phase I has already demonstrated a scalable fabrication process that can reduce metasurface cost to dollars per chip. MetaDot’s active probing architecture and transparent substrate avoids the photon-starved, low-SNR operation of fluorescence and other detection technologies. Instead, MetaDot provides high signal-to-noise ratio (SNR) and highly accurate and repeatable measurements. Existing pathogen test systems are often costly, non-portable, or require operation by a laboratory technician. In contrast to commercial surface plasmon resonance (SPR) detection, the proposed metasurface has many times more microscopic surface area, increasing overlap between pathogens and the evanescent electric-field of the reflected light. Compared to existing SPR sensors, the MetaDot system reduces cost and size by two to three orders of magnitude. Unlike optical techniques based on external labeling, resonance shifting in the MetaDot metasurface operates as a reporter of the pathogen binding phenomena in a label-free fashion and enables transduction of the capturing event directly as a shift in the polarization of the reflected light. The MetaDot reflection probe geometry separates the optical path from the test solution, minimizing scatter and enabling extremely low noise and high sensitivity.The MetaDot reader is designed to use common commercial off-the-shelf (COTS) optics and electronics and will be easy to use and inexpensive to manufacture. MetaDot can be extended to detect a wider range of pathogens for point-of-care (PoC) applications as diverse as first-aid wound infection diagnosis, on-site dental pathogen assessment, and screening for infectious diseases at ports of entry.