CAREER: Bioinspired optical sniffer based on microtoroid resonators and science and technology convergence

The goal of this Faculty Early Career Development (CAREER) project is to create an optical “nose” as sensitive as a bloodhound’s and as selective as an insect’s. Animals' noses can distinguish among many thousands of different chemicals. Smell plays a critical role in chemical communication, sensing danger, and navigation. Thus, a biomimetic sensor based on an olfactory system would have tremendous benefits. This project will combine optical sensing technology that can detect changes in how light interacts with molecules with engineered olfactory receptors. Pattern recognition will be accomplished using artificial intelligence. It is anticipated that these advances will enable the detection of extremely low concentrations of biological and chemical targets relevant to a diverse range of diseases, environmentally important chemicals, and threats. In parallel, a do-it-yourself (DIY) refractometer kit will be developed to introduce middle and high-school students to optical engineering concepts. Lessons involving optics and food and water quality testing with refractometers will be developed to build a sustained STEM pipeline and to democratize science for a better world. A biomimetic sensor based on an olfactory system could automate, with greater sensitivity, tasks that can currently only be performed by humans and animals. Existing bioinspired electronic (e-) noses have not been widely adopted due to poor stability, slow response speed, and selectivity artifacts. In the proposed work, the biochemical sensing field will be advanced by creating an optical nose with improved sensitivity and selectivity by incorporating computationally designed olfactory receptors, which are superior to existing e-nose polymer coatings, onto whispering gallery mode (WGM) microtoroid optical resonators. WGM resonators have previously been widely used for biological and chemical sensing because of their high sensitivity compared to electronic sensors, but WGM resonators have never been used in concert with natural olfactory receptors for VOC detection due to the challenge of designing, producing, binding, and maintaining the functionality of these receptors. Here the field of WGM biochemical sensing will be advanced through a convergence of computational molecular design, synthetic biology, specialized surface chemistry approaches and photonic advances for multiplexing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.