Investigation and optimization of mechanical effects on the performance of microneedles

Microneedles are advanced devices that ensure efficient, painless transdermal delivery of drugs and biomolecules, with significant potential in biomedical applications. In this study, a novel silicon carbide-based microneedle design was proposed, featuring a tip integrated with eight lumens that optimized fluid flow and minimized blockages, thereby improving the efficiency and reliability of transdermal therapy. The designed silicon carbide-based microneedle has a length of 350 μm, and its inner and outer diameters are 30 and 52 μm, respectively. The tip of the microneedle is conical and has an angle of 29.148 degrees. Each of the eight lumens in the lumen region in the conical section is 10 μm in diameter, equal to each other, uniformly distributed to ensure consistent flow. In the Mesh Convergence Analysis, the most suitable mesh was selected as the Normal mesh, which was obtained by using Coarse, Normal and Fine meshe structures consisting of 17790, 55717 and 237174 elements, respectively. The study performed Finite Element Analysis of the microneedle with a sensitivity of 0.001, investigating its mechanical and fluidic properties. The analysis considered the fluids water, ethanol, blood, and glycerol. The mean maximum pressures in the lumens and the total flow rates were obtained at inlet pressures ranging from 10 Pa to 100 Pa in 10 Pa increments. The flow rates through the lumens exhibited a near-linear relationship with inlet pressure, maintaining a linearity that exceeded 99%. Additionally, the mechanical behavior of the microneedle was investigated under axial and bending loading. This design, utilizing silicon carbide and a multi-lumen structure, was observed to improve the performance, mechanical stability, and fluid delivery efficiency of the microneedle compared to previous models. The study presented comprehensive integration of mechanical and fluid analyses combined with the strategic application of silicon carbide.