Preparation of Gelatin-Based Conductive Microneedles Utilizing a Hydrogen Bonding Dissociator

Microneedles (MNs) are widely utilized in percutaneous drug delivery systems and represent a crucial approach for drug or vaccine administration. The conductive MNs further enhance the controllability and functionality of these devices, thereby expanding their potential biomedical applications. Given its high biocompatibility and degradability, gelatin emerges as an ideal material for fabricating MNs. However, owing to its inherent hydrogen bonding, gelatin solutions exhibit high viscosity and tend to solidify at room temperature, thus limiting their processability in the preparation of gelatin MNs. In this study, a novel approach was proposed to enhance the fluidity of the gelatin solution and reduce its solidification temperature by adding citric acid as a hydrogen bonding dissociator, thereby facilitating its use in MN fabrication. Furthermore, citric acid functioned not only as a hydrogen bonding dissociator but also as a dopant in the 3,4-ethylenedioxythiophene (EDOT) polymerization process, demonstrating dual functionality and effectively yielding gelatin/poly 3,4-ethylenedioxythiophene (PEDOT) MNs. This research presents an innovative strategy for developing gelatin-based MNs and advances their potential applications in intelligent medical fields.