3D-Printed Microneedles with Controlled Structures for Drug Delivery Study in an Ex Vivo Model

MN arrays are highly beneficial for transdermal drug delivery, primarily due to reduced pain and improved compliance. However, complex processing and restricted design freedom limit traditional fabrication. We utilized stereolithography (SLA) 3D printing as a breakthrough method to achieve the one-step production of MN arrays with customized geometries (structure, size, tip angle), enabling tunable release profiles and eliminating cumbersome manufacturing steps. After fabricating conical and grooved MN arrays and validating them in an ex vivo porcine skin model, we confirmed their functionality. Notably, the grooved design provided excellent penetration, requiring only 2.2 N of force for full insertion (at 18.92° tip angle), and demonstrated an enhanced drug loading capacity of 4.8 μg released over 2 h. These results underscore the significant potential of 3D-printed, channel-structured MN arrays as a new generation of high-performance transdermal delivery devices.