Development of mems-based microneedles for biomedical applications

Abstract

In this work, Silicon (Si) in-plane microneedles are designed for precise transdermal drug delivery and localized blood sampling with minimal invasion of the human tissue. A range of loading conditions acting on the microneedle is examined to ensure mitigation of crack initiation and propagation. In addition, a criterion is proposed for design of microneedle with optimized dimensional constraints that can withstand maximum forces based on theoretical models. The proposed formulation is then simulated using a commercial finite element simulation tool "ANSYS". A novel fabrication process to realize these microneedles, along with integrated piezoelectric sensors (AlN) at various lengths has been proposed in this work. The surface micromachined piezoelectric sensors form an integrated force sensing feedback system. In this thesis, a novel theory-based model is proposed that predicts drift velocity of blood-flow through micro-channels fabricated within microneedles. The profile of blood flow in the microneedles is determined by solving the conservation of momentum equation of the liquid phase, coupled with the force balance equations.