Fast and controllable elastocapillary flow channels using suspended membranes

The ability to control the fluid velocity and flow rate in microfluidic paper-based analytical devices (μPADS) will help to enable more sensitive and flexible point-of-care (POC) diagnostics. We present an elastocapillary channel design, for fluid flow in porous membranes, which enables an increase in flow velocity by a factor of up to 4.45 compared with a porous membrane used in a standard, non-suspended, format. The increase in flow rate is controllable with varying channel width, and is enabled by using an elastocapillary action, where the flexible porous membrane is suspended over a rigid substrate and deformed during fluid imbibition. This enabling technology is particularly useful in POC diagnostics, where small samples need be rapidly transported and mixed with minimal loss of volume.