Experimental and numerical studies of deformation of truncated-cone-shaped poly(L-lactic acid) microneedle during insertion

Abstract

Abstract To explore minimally invasive and hypodermic access for in-body sensing, polymer microneedles of 2 mm in length have been studied. Sharper tips are desirable to reduce pain, however, the mechanical strength of such tips is low. To design polymer microneedles that do not plastically deform, the deformation behavior of poly(L-lactic acid) microneedles with different tip diameters was investigated by simulation and experiment. It was found that the plastic deformation of the tip may increase the insertion force. The minimum insertion force was approximately 200 mN for microneedles with a tip diameter of 80 μm, which were inserted without plastic deformation.