Invasive PLA microneedle fabrication applied to drug delivery system

This study fabricated a novel biodegradable polymer microneedle patch. First, a master microneedle array was fabricated using the micro electro-mechainal system (MEMS) process. Polydimethylsiloxane (PDMS) was then utilized to fabricate the microneedle mold. Finally, the biodegradable polymer polylactic acid (PLA) microneedle patch was fabricated by micro hot embossing. The Taguchi method was applied to identify the optimal process parameters for micro hot embossing the PLA microneedle. The sizes of the original microneedle and that of the PLA microneedle were compared, through the transfor by PDMS mold. Next, a numerical simulation and the skin puncture test were used to confirm the PLA microneedle patch fabrication using the optimal process parameters. During numerical simulations, this study used dynamic finite element software (ANSYS/LSDYNA) to simulate the process of the PLA microneedle being inserted into skin. Based on the mechanical properties of different skin layers and the material failure criterion, insertion force and stress variation during PLA microneedle insertion into skin were determined. In a skin puncture experiment, transepidermal water loss (TEWL) was measured to determine whether the PLA microneedle damaged the stratum corneum and decreased the water protection capacity of skin.