Industrial-Scale hot embossing of PLA microneedles enabled by sheet processing and PEG Plasticization: Synergy of energy efficiency and mechanical Adaptability

This study resolves PLA microneedle production bottlenecks via sheet-based hot embossing and PEG plasticization. Replacing granules with sheets reduced energy by 40 % using TC4 molds (>200 cycles). Orthogonal tests prioritized pressure (F = 76.8), achieving 82 % yield at 200 ± 5°C/190 ± 10 s/0.2 MPa. PEG (60 wt%) enhanced flexibility via hydrogen bonds, maintaining 92 % skin penetration and 95 % drug release. Resultant microneedles matched commercial hollow efficacy (p > 0.05) with 82 % lower pain (0.6 g vs. 3.4 g). The revealed flow-degradation mechanism guides scalable manufacturing.