Fabrication and Characterization of Porous Microneedles for Enhanced Fluid Injection and Suction: A Two-Photon Polymerization Approach

Porous microneedles (MNs) offer broad advantages such as fluid capture and filtration. Compared to hollow MNs, fluid injection through porous MNs causes a broader diffusion spread. Herein, three MN designs with a constant pore size and controlled pore locations are fabricated and compared, using two-photon polymerization (2PP), by examining factors such as diffusion spread, mixing capabilities, and mechanical resilience. Results show that the porous MN can cover 16 times the injection area than that of the hollow MN. Porous MNs also show good mixing capabilities with two fluids. Mechanical compression results reveal that one porous MN can withstand a load of 0.6 N.