Modeling, characterization, and fabrication of bell-tip microneedle array by diffraction and self-aligned lens effects

Microneedle arrays have been proposed in a wide range of biomedical applications, such as transdermal drug delivery and sensing. However, scalable manufacturing process precise microneedle fabrication the has challenged. This paper demonstrates UV-lithography-based one-step fine-tuned bell-tip microneedles using combination light diffraction self-aligned lens effect. Microscale photopatterns can derive predictive patterns where higher intensity at center photopattern solidifies liquid photoresist forms microlens shape manner. The through focuses down to sharp point form conical for body microneedle. Then propagation vertex cone causes emission, creating fine bell-tip. described behavior was characterized explained terms distribution from based on extended Fresnel–Kirchhoff model. optics finite element analysis software used verify distribution. step-by-step demonstrated biocompatible photosensitive resins validated attenuation cross-linking energy. 20 × microneedles' array able be fabricated predicted Finally, with various shapes heights same substrate by single exposure, demonstrating numerous achievable method.