Tympanic membrane (TM) perforations, primarily induced by middle ear infections, the introduction of foreign objects into the ear, and acoustic trauma, lead to hearing abnormalities and ear infections. We describe the design and fabrication of a novel composite patch containing photocrosslinkable gelatin methacryloyl (GelMA) and keratin methacryloyl (KerMA) hydrogels. GelMA-KerMA patches containing conical microneedles in their design were developed using the digital light processing (DLP) 3D printing approach. Following this, the patches were biofunctionalized by applying a coaxial coating with PVA nanoparticles loaded with gentamicin (GEN) and fibroblast growth factor (FGF-2) with the Electrohydrodynamic Atomization (EHDA) method. The developed nanoparticle-coated 3D-printed patches were evaluated in terms of their chemical, morphological, mechanical, swelling, and degradation behavior. In addition, the GEN and FGF-2 release profiles, antimicrobial properties, and biocompatibility of the patches were examined in vitro. The morphological assessment verified the successful fabrication and nanoparticle coating of the 3D-printed GelMA-KerMA patches. The outcomes of antibacterial tests demonstrated that GEN@PVA/GelMA-KerMA patches exhibited substantial antibacterial efficacy against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, cell culture studies revealed that GelMA-KerMA patches were biocompatible with human adipose-derived mesenchymal stem cells (hADMSC) and supported cell attachment and proliferation without any cytotoxicity. These findings indicated that biofunctional 3D-printed GelMA-KerMA patches have the potential to be a promising therapeutic approach for addressing TM perforations.

This study describes the processing of microneedle (MN) arrays with three different heights of arrowhead (600 µm (A1), 800 µm (A2), and 1000 µm (A3)), pyramid (600 µm (P1), 800 µm (P2), and 1000 µm (P3)), and turret (600 µm (T1), 800 µm (T2), and 1000 µm (T3)) designs using a digital light processing (DLP)-based 3D printing method. The 3D-printed MNs were examined for their morphological characteristics and mechanical performance. Scanning electron microscopy (SEM) imaging confirmed that all of the MNs were fabricated without fracture or bending. Each design exhibited distinct structural characteristics: arrowhead MNs displayed a well-defined morphology with sharp tips, pyramid MNs showed slight layering, and turret MNs, characterized by a wider base and sharp tips, had a smoother surface compared to the other designs. Mechanical tests revealed that the arrowhead MNs carried less load and were more prone to bending, while the pyramid and turret designs provided higher mechanical stability and penetration capacity. The pyramid design (P3) showed the highest mechanical strength, while turret MNs offered a more stable performance despite lower penetration capacity. These findings highlight the critical role of geometric design in optimizing MN performance for effective transdermal drug delivery.