Characterization of a wireless implantable infusion micropump for small animal research under simulated in vivo conditions

A wirelessly-operated implantable site specific drug delivery micropump with on-demand control of dosing for chronic infusion applications in small laboratory animals is presented. The system includes an electrolysis-based actuator, refillable drug reservoir, wireless powering, and a check valve. Micropumps were fabricated, assembled, and tested in simulated in vivo conditions. As expected, power transfer decreased when varying the distance and angle between the transmitter and receiver coils resulting in a drop in flow rate; these conditions replicate variations in pump orientation with respect to an external transmitter coil as would be the case in a device placed in a freely moving animal. Stationary micropumps operated wirelessly successfully delivered 30 μL doses daily for seven days as required by an anti-cancer application. The average flow rate across the pumps was 1.93 ± 0.35 μL/min. Flow rate performance was not significantly affected by simulated in vivo conditions such as back pressure of up to 20 mmHg and delivering solutions with viscosities of up to 6 cP.