A remotely adjustable check-valve array with an electrochemical release mechanism for implantable biomedical microsystems

In this paper, we present a remotely adjustable check-valve array with an electrochemical release mechanism for implantable biomedical microsystems. A SU-8 polymer layer deposited on the top of a gold sacrificial layer was used as the valve structural material. A constant DC current obtained via a telemetry link was used to electrochemically dissolve the gold sacrificial layer and activate the valves. 3x3 and 4x4 arrays each containing three different size valves (50x50, 100x100 and 200x200 pm) were fabricated and tested. A current density of 35 mA/cm(2) resulted in the dissolution of a 3000Angstrom gold sacrificial layer in 30 seconds with the final release completed in 1-2 minutes.