Design and simulation of microfluidic components towards development of a controlled drug delivery platform

Microneedle and micropump form important parts of a controlled drug delivery system. This work focuses on the finite element based analysis of Poly Dimethysiloxane (PDMS) membrane based piezoelectric micropump and SU-8 based hollow microneedles. For the micropump, valveless diffuser/nozzle based design is used where the divergence angle of 150 is found to be optimum with flowrate of about 0.75m/s. Maximum velocity is seen at the inlet of the two diffusers. The volume rate differs from 18.5 mu l/min at inlet to 24 mu l/min at outlet. The flow is laminar in the pump chamber with Reynold's number varying from 5 to 40. PZT-5H is chosen as the actuator since it gives maximum deflection at an applied voltage as compared to other probable actuators. The fundamental mode of vibration of the piezoelectric actuator is at 33.018 KHz giving maximum displacement of 23.8 mu m. A hollow cylindrical SU-8 microneedle shall be able to successfully pierce the skin overcoming the skin resistance force of 0.02N per needle. Maximum Von Mises stress generated on the microneedle tip on skin insertion is 6MPa which is lesser than the yield strength of SU-8 which is 32MPa.