Controllable-pore porous microneedles for high-speed extraction and biomarker detection of interstitial fluid

Porous microneedles have attracted considerable attention as minimally invasive tools for interstitial fluid sampling and biomarker analyses. However, existing porous microneedle fabrication methods often suffer from low extraction efficiency, primarily because of the inherent trade-off between increasing porosity and maintaining sufficient mechanical strength. Herein, we present a novel approach for fabricating porous microneedles with controllable pore sizes and enhanced extraction performance. Monodisperse polylactic acid microspheres, produced via microfluidic techniques, are thermally bonded to form porous microneedles with interconnected pore networks originating from the connected voids between the microspheres. By precisely adjusting the microsphere diameter, we optimize the pore size to achieve high extraction efficiency while preserving structural integrity. Following surface t…