CAREER: Compact digital biosensing system enabled by localized acoustic streaming

Rapid, portable, and accurate diagnostic testing is of great importance to improve the quality and accessibility of healthcare. However, the performance of existing rapid and portable testing methods is often not sufficient for complex diseases such as infectious diseases, cancer, and cardiovascular diseases. The major goal of this CAREER project is to develop a new digital testing platform that offers high detection sensitivity and quantification accuracy without sacrificing the simplicity and the portability. The new testing platform is enabled by the unique fluid phenomenon induced by a vibrating capillary and 3D printed microdevices. Upon the successful completion of this project, integrated devices that can detect low abundance nucleic acid and protein biomarkers without the need of dedicated instrument and laboratory space will be developed. Such devices will have great potential to deliver high quality medical testing to a broad population including underserved communities and resource limited regions. This project is highly multidisciplinary and will produce low cost, and compact instrumentation. It therefore creates unique educational opportunities for students with different backgrounds. The proposal will enable 1) improved learning outcomes for students in quantitative chemical analysis lab through implementing project- and problem-based learning concepts to the curriculum; 2) novel microscale analytical chemistry experiments for undergraduate students, e.g., vibrating sharp-tip powered microfluidic enzymatic assay; 3) a research program that trains students to solve research problems using multidisciplinary approaches. This project is to develop an integrated solution to perform complete digital bioassays under a point-of-care (POC) setting thereby addressing the unmet need of developing high performance POC tests. The proposed method is enabled by controlling the vibration of sharp tips, which can generate localized and individually addressable acoustic streaming in microchannels for fluid control and droplet generation. To achieve the proposed impact, three aims will be pursued: 1) Elucidate the sharp-tip droplet generation process through numerical modeling and streaming analysis and demonstrate a POC nucleic acids detection system; 2) Develop a simple dual flow droplet generation system for performing digital ELISA; 3) Demonstrate an integrated the sample processing system enabled by vibrating sharp-tip and composable microfluidic plates. This project will lead to a flexible biosensing platform that can be easily adapted to measure either low abundance nucleic acids or protein biomarkers. It will also advance the fundamental understanding of the acoustic streaming in immiscible fluids and expand the utility of acoustic streaming for complex fluid, droplet, and particle manipulations. 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.