Evaluation of geometrical effects of microneedles on skin penetration by CT scan and finite element analysis

Computerized tomography (CT scan) imaging and finite element analysis were employed to investigate how the geometric composition of microneedles affects their mechanical strength and penetration characteristics. Simulations of microneedle arrays, comprising triangular, square and hexagonal microneedle base, revealed a linear dependence of the mechanical strength to the number of vertices in the polygon base. A laser-enabled, micromoulding technique was then used to fabricate 3x3 microneedle arrays, each individual microneedle having triangular, square or hexagonal base geometries. Their penetration characteristics into ex-vivo porcine skin, were investigated for the first time by CT scan imaging. This revealed greater penetration depths for the triangular and square-based microneedles, demonstrating CT scan as a powerful and reliable technique for studying microneedle skin penetration.

© 2016. This author's accepted manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/