Fabrication and characterization of a biomimetic hydrogel check valve

A biomimetic hydrogel valve that combines the characteristics of both active and passive valves is fabricated and characterized. The microscopic valve consists of a pair of photopolymerized hydrogel bi-strips with different pH-sensitivities. At physiological pH, the bi-strip undergoes changes in both shape and size to form a valve. The valve mimics anatomic venous valves both functionally and structurally, allowing fluid flow in one direction while restricting flow in the opposite direction. At an applied pressure of 0.71 psi, the forward flow rate was 140 /spl mu/L/min, compared to a reverse leakage rate of 2.3 /spl mu/L/min at the same pressure. The valve not only provides directional control of the flow, but also reversibly activates (swells) or deactivates (shrinks) based on the chemical environment of the local fluid. The sealing capabilities of the hydrogel materials are also explored.