Title:  Capillary Flow Control on Paper for Point-of-care Testing

Committee: 

Dr. Sarioglu, Advisor

Dr. Frazier, Chair

Dr. Emelianov

Abstract: The objective of the proposed research is to develop a novel technique to control capillary flow on paper by simply imprinting roadblocks on the flow path with water-insoluble ink and utilizing the gradual formation of a void between a wetted paper and a sheath polymer tape to create timers. Timers are drawn at strategic nodes to hold the capillary flow for the desired period and thereby enable multiple liquids to be introduced into multi-step chemical reactions following a programmed sequence. The ability to sequentially deliver different reagents into a reaction via programmable timers imprinted on paper makes it possible to automate multi-step assays, that otherwise could only be performed in laboratories or with manual intervention. Using our technique, we developed (1) an LFA with built-in signal amplification to detect human chorionic gonadotropin with an order of magnitude higher sensitivity than the conventional assay, (2) a point-of-care (POC) device to extract DNA from bodily fluids (blood, saliva, and urine) without relying on laboratory instrument, and (3) a fully-integrated POC toolkit for multiplex molecular diagnosis of SARS-CoV-2 and influenza A and B viruses from saliva. To further improve the presented technique, we propose (1) reversible manipulation of the timers by introducing new physical or chemical processes and (2) further application of the presented technique to make complex and traditionally labor-intensive assay available in assay formats as simple and frugal as conventional LFA.