Contoured elastic-membrane microvalves for microfluidic network integration

A contoured elastic-membrane microvalve is presented that enables integrate d microfluidic processing at the network level. This method takes advantage of two ideas to improve performance: flexible elastic membranes (which ena ble high-performance shutoff and reduced footprint), and three-dimensionall y contoured valve geometries (which reduce dead volume, improve fluidic pri ming and reduce susceptibility to cavitation at high fluid velocities). We describe the use of laser-induced etching for microfluidic manifold fabrica tion discuss the nonlinear load-deflection behavior of elastic membranes th at can occur below 30 psi, and present pow-rate data for microvalves under inlet pressures of 0-20 psi with zero applied membrane pressure. Valve-clos ure data for inlet pressures of 0-30 psi are presented for fully assembled microvalve structures. The microvalve structures under test were capable of turning off flows of >20 mu L/s. These pow rates were shown to be limited by inlet and outlet pow resistances and not by the valve structure itself; so that higher maximum flow rate capabilities should be readily achieved.