Biodegradable porous microneedles via PLA microspheres for rapid ISF extraction

Abstract

Microneedles (MNs) have been conceived as a novel technique for painless extraction of interstitial fluid (ISF) as a minimally invasive approach. Especially biodegradable polymeric MNs with porous structure have attracted extensive attention in recent years. In this study, a simple yet innovative technique to fabricate porous MNs from polylactic acid (PLA) microparticles with thermal treatment is proposed. The MNs fabrication process is comprised of single emulsion solvent evaporation method and thermal treatment which is low-cost and easy to perform. The dimension of the thermal-treated PLA MNs is 1200 μm in length and have sharp tips below 100 μm. Moreover, the porous MNs have robust mechanical property to penetrate Aluminum foil. As a result, the MN array can extract 5 mM glucose contained ISF rapidly from 2% skin-mimicking agarose gel within 5 minutes after thermally treated at 200 and 210 degrees centigrade for 2 hours. The proposed PLA porous MNs can extract ISF rapidly which shows a promising perspective in combing biosensors for point-of-care (POC) testing of biomarker concentrations in body fluid.