3D-Printed Personalized Hydrogel Patch for Skin Lesion Prevention and its Features: The Role of Rheology

Personal Protective Equipment (PPE) such as Filtering Face Piece nº2 (FFP2) masks and surgical masks are widely used by healthcare professionals (HCPs) and the general public (GP) for extended periods, leading to skin issues like rosacea and maskne. An innovative approach involves developing personalized 3D-printed hydrogel-based patches with incorporated active ingredients to address PPE-related skin lesions. This study focuses on creating and characterizing personalized patches containing metronidazole (Met) and salicylic acid (SA) to target rosacea and maskne, respectively, resorting to 3D printing technology. Characterization studies were conducted on Gelatin-Tannic Acid-based (Gel/TA) hydrogels with added Met and SA to assess changes in mechanical properties. Gelation temperature and time were determined using a rheometer, while extensibility, burst strength, and adhesivity were measured using a texture analyzer. Printability conditions were tested on an Allevi2 printer. Results showed similar gelation temperatures for Gel/TA and Gel/TA-Met, while Gel/TA-SA exhibited a lower temperature, 41.11 ± 0.79 ℃ and 40.44 ± 0.40 ℃ respectively. Gelation time was consistent across formulations (20.69 ± 1.68 s). Adhesivity improved with added active ingredients, and burst strength increased significantly with Met. Both formulations with active ingredients showed improved extensibility. Width and Length indexes calculation defined the best printing conditions for each tested formulation. Gel/TA and Gel/TA-Met shared the same printability conditions, 42ºC, 25 Psi and print speed of 30 mm/s, unliked Gel/TA-SA which was 36ºC, 30 Psi and print speed of 30 mm/s. The rheological and mechanical properties of these formulations, along with defined printing parameters, indicate their potential for 3D printing personalized patches to treat various PPE-related skin lesions concurrently.