US11697008B2

A microneedle assembly and a method of fabrication the assembly are provided. The microneedle assembly includes an array of microneedles attached to a base. Each of the microneedles comprise a tip, a needle shaft and a plurality of cantilevered barbs protruding outwardly from the needle shaft, where a plurality of the microneedles include two or more of the cantilevered barbs arranged in a series of concentric rings along the needle shaft of each of the plurality of microneedles. The microneedle assembly may be fabricated using a 3D printing technique, where one or more cantilevered layers are formed by exposing a photocurable liquid resin including monomer material to a light source to create initially horizontal, cantilevered barbs having a crosslinking gradient, and rinsing to remove an amount of un-crosslinked monomers from the cantilevered layers to induce curvature in the cantilevered barbs extending towards a direction of the lower crosslinking.