Automatic Time-Dependent Flow Cut-Off System for Paper-Based Microfluidic Devices Using Erodible Polymeric Bridge

Abstract. An automatic time dependent flow cut-off system for volume control and reagent delivery applications in paper-based microfluidic devices has been developed. This system provides the ability to stop the fluid flow in porous media without external actuation through the use of a rapid dissolvable polymer film (referred to as a polymeric bridge). In this study, we quantitatively describe how this system responds to the dimensions of the polymeric bridge. Fluid crossing the polymeric bridge is stopped at distance that can be precisely pre-specified through the control of the dimensions of the polymeric bridge. In this work, we also show that the film can also be used as a reagent delivery device. This technology could be an excellent low-cost method for reagent delivery and volume control in paper-based analytical devices. Moreover, this method can be especially useful for time-sensitive or multi-step reactions/assays without compromising the simple, inexpensive, portable, and easy to use characteristics of paper-based microfluidic devices.