The broader impact/commercial potential of this Small Business Technology Transfer Program (STTR) Phase I project is to provide 7.7 M women in the US struggling with infertility a quantitative and affordable way to assess their ovulatory health. This progesterone biosensor is the first outcome of a platform technology that to expand at-home blood diagnostics and analysis for remote health care. This project will produce the first of a novel class of inexpensive, real-time, and point-of-care biosensors that will impact multiple fields and markets, such as human and animal healthcare, agriculture, national defense, and biomanufacturing. The initial application will further expand access to quality health care for underserved populations. The proposed project develops a device to measure progesterone at clinically meaningful low levels from blood samples for patients including women who have never been pregnant, women with ovarian disorders, pre-menopausal and post-menopausal women. This Small Business Technology Transfer Program (STTR) Phase I project is developing an entirely novel class of biosensors for physiologically important molecules with progesterone being the first example. The technical hurdles to be addressed by the proposed work in this proposal are to first translate optical transduction technology onto low-cost paper strips. Furthermore, determine if this new class of biosensors can measure molecules, such as progesterone, from blood to criteria required for clinical use and commercialization from paper test strips. Lastly, determine the impact of clinical requirements for a low-cost and portable measurement device to read the paper lateral flow strips. 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.