Mechanical strength evaluation of crystalline poly(L-lactic acid) fabricated by replica micromolding for bioabsorbable microneedle devices

Abstract

In the development of biomedical microdevices, material properties are the key to fulfilling specific application requirements. Here, we developed a fabrication method for a microneedle device made of the bioabsorbable polymer poly(L-lactic acid) (PLLA). The device has a high aspect ratio feature of 500 μm in width and 2 mm in length and uses vacuum-assisted micromolding. In addition, the material properties of the microneedles were investigated under different process conditions. Crystallinity was evaluated using X-ray diffraction analysis, and mechanical strength was determined using a newly developed microscopic three-point bending test apparatus for micromolded sub-millimeter samples. This information about fabrication processes and material properties is an important guiding principle for the development of polymer microdevices.