Multifunctional rotational active valve for flow control in paper-based microfluidic devices

Abstract

In paper-based microfluidics, the development of a robust and multi-role valve mechanism is important for flow control to perform multistep biochemical assays. The previous valve designs were complex, limited in their operational capabilities to simply ON/OFF functionality, required complex circuitry and auxiliary devices for valve actuation, or were unfit for friendly user operation. Herein, we present a multifunctional, simple, robust and cost effective rotational active valve (RAV) for paper-based microfluidics devices. In addition to ON/OFF, it achieves variable flow velocity by varying the contact area of RAV channel, by varying the RAV channel length, or by changing the RAV channel width. The functionality was demonstrated in paper-based microfluidic devices for sequential delivery with intermixing, multi-reagent valve regulation with washing step, and fluid distribution to multiple delivery zones. Finally, we conducted a multistep biochemical assay for the detection of total protein, uric acid and albumin protein in human serum at various concentration (dilution ranges from 40% to 100%) using RAV. We believe that our RAV can solve complex biochemical assays in paper-based devices with potential to be commercialized due to its cost-effectiveness, easy fabrication and robust nature of flow control enabling to achieve a viable point-of-care diagnostic platform.