Fabrication of customized microneedle with high 3D capability and high structural precision

Advanced 3D fabrication techniques are essential for the processing of 3D devices, which mainly focusing on excellent 3D fabrication capability and high structural precision. Although 3D printing technology allows for the creation of complex 3D structures with extensive customization, it faces notable challenges in achieving precise micro/nanostructures within materials due to incomplete resin curing bonds. Here, we propose integrating projection micro-stereolithography (PμSL) with femtosecond (fs) laser Bessel beam drilling to create 3D structures with advanced customization, precise structures (including size accuracy and aspect ratio), and efficient processing. Starting with the drilling process using Bessel beams, we have achieved micro-holes with a diameter of approximately 1μm and the aspect ratio reached 1017:1 on 3D printed items by regulating the transparency and elasticity of the products. Furthermore, we have applied this technology to produce tailor-made microneedles, including slanted-tip microneedles and porous microneedles, demonstrating its ability for extensive, efficient micro-hole processing with a peak drilling speed of 200,000 holes per second. This technology offers an innovative approach to creating three-dimensional devices with intricate cavity structures, and its impressive processing capabilities suggest potential for broad industrial implementation.