Bio-inspired design and finite element analysis of polymer composite microneedles with hollow architecture

Interstitial fluid (ISF) is a body fluid found in dermal cells containing different types of biomarkers. Microneedles have been developed for transdermal applications such as drug delivery and the extraction of dermal fluids. In this study, a micro digital light processing (μDLP) technique is utilized to fabricate a fountain pen inspired hollow microneedle (HMN) patch. This research focused on evaluating the optimal design parameters and print angle of HMN with high resolution. Furthermore, ANSYS finite element analysis (FEA) evaluated that the maximum von-Mises stress of individual needle tip is 3.291 MPa which is greater than the skin resistance value of 3.183 MPa. Simple stress, such as tensile or compressive stress, measures force per unit area applied in one direction. In contrast, von-Mises stress combines stresses from multiple directions. This approach provides a more accurate prediction of failure in microneedles under complex loading conditions. In addition to that, the maximum total deformation is 6.1034 μm which is smaller than the length of the microneedle. Moreover, Silicon Carbide (SiC) is introduced as filler ceramic material to fabricate the hollow microneedle patch.