Microfluidic gasketless interconnects sealed by superhydrophobic surfaces.

Abstract

Existing methods for sealing chip-to-chip (or module-to-motherboard) microfluidic interconnects commonly use additional interconnect components (O-rings, gaskets, and tubing), and manual handling expertise for assembly. Novel gasketless superhydrophobic fluidic interconnects (GSFIs) sealed by transparent superhydrophobic surfaces, forming liquid bridges between the fluidic ports for fluidic passages were demonstrated. Two test platforms were designed, fabricated, and evaluated, a multi-port chip system (ten interconnects) and a modules-on-a-motherboard system (four interconnects). System assembly in less than 3 sec was done by embedded magnets and pin-in-V-groove structures. Flow tests with deionized (DI) water, ethanol/water mixture, and plasma confirmed no leakage through the gasketless interconnects up to a maximum flow rate of 100 μL/min for the multi-port chip system. The modules-on-a-motherboard system showed no leakage of water at a flow rate of 20 μL/min and a pressure drop of 3.71 psi. Characterization of the leakage pressure as a function of the surface tension of the sample liquid in the multi-port chip system revealed that lower surface tension of the liquid led to lower static water contact angles on the superhydrophobic-coated substrate and lower leakage pressures. The high-density, rapidly assembled, gasketless interconnect technology will open up new avenues for chip-to-chip fluid transport in complex microfluidic modular systems.