Micromolding‐Based Fabrication of Dissolvable Microneedles: An Economical and Scalable Approach for Transdermal Drug Delivery

Microneedles have emerged as a revolutionary approach in transdermal drug delivery, offering a minimally invasive, pain‐free, and efficient alternative to conventional drug administration methods. In this study, two distinct microneedle designs—cone‐shaped and cone–cylinder‐shaped—were fabricated in 5 × 5 and 5 × 10 arrays, respectively, utilizing a polymer matrix composed of carbohydrate‐based dissolvable materials (carboxymethylcellulose, trehalose, and hyaluronic acid) and biocompatible polymers (PVP K‐90). Especially, a specific feature of the PDMS mixture with a weight ratio of 10:0.15 (prepolymer to curing agent) facilitates the separation of the PDMS mold from the master structure whole demolding process on account of its flexibility. Rheological analysis at 36°C confirmed the pseudoplastic nature of the polymer solution, ensuring optimal flow behavior for application. Mechanical compression tests demonstrated that cone‐shaped microneedles exhibited superior mechanical strength, requiring 0.28 ± 0.03 N/needle for failure under axial loading, whereas cone–cylinder‐shaped microneedles required only 0.17 ± 0.04 N/needle, indicating lower mechanical stability. Therefore, microneedle insertion based on mechanical compression tests confirmed that a 50‐ μ m displacement force was sufficient to penetrate the stratum corneum and reach the epidermal layer, validating their potential for effective skin delivery. Furthermore, in vitro cytocompatibility assessments using HEK293 cells confirmed that the polymer solution and its individual components were biocompatible. These findings underscore the critical role of microneedle geometry and polymer composition in optimizing mechanical integrity and dissolution properties. Future research should focus on enhancing drug‐loading capacity, fine‐tuning polymer‐to‐sugar ratios, and conducting in vivo studies to further validate their clinical applicability. This study provides a robust foundation for the development of dissolvable polymer microneedles with stainless steel pins as a scalable, biocompatible, and efficient transdermal drug delivery platform.