Numerical simulation and computational modeling of interstitial fluid extraction processes in hollow microneedle arrays.

Microneedle patches for interstitial fluid (ISF) extraction have significant potential in minimally invasive diagnostics, but the underlying dynamics of fluid transport remain insufficiently understood. This study presents a hierarchical computational fluid dynamics (CFD) model to systematically investigate the fluid transport dynamics within a hollow microneedle array during the ISF extraction process. The research focuses on the contributions of geometric parameters, such as lumen diameter and array spacing, to the extraction rate per unit area, comparing the fluid dynamics behaviors across 2D simplified structures, 3D single-needle structures, and periodic array structures. Experimental validation was performed using 3D-printed hollow microneedles in an agarose gel model. This research may advance the theoretical understanding and practical application of hollow microneedles in fluid extraction.