A novel injectable Sericin/Nano-hydroxyapatite hydrogel as a dermal filler for soft tissue augmentation.

With the rapid advancement of medical aesthetics, particularly the expanding market for wrinkle reduction and facial rejuvenation, the demand for dermal fillers continues to rise. Injectable materials derived from natural sources offer significant potential in cosmetic applications due to their superior biocompatibility and bioactivity as soft tissue augmentation fillers. In this study, a novel Sericin/Nano-hydroxyapatite hydrogel was synthesized using ultrasonic technology, eliminating the need for cross-linking agents and simplifying the preparation process. The results showed that the hydrogel could form a gel in a few minutes under ultrasonication. Characterization analyses revealed a uniform porous structure. The hydrogel exhibited a swelling degree of over 10-fold and excellent mechanical properties, including injectability. Furthermore, the hydrogel demonstrated strong antioxidant properties, capable of mitigating inflammatory responses. Cytotoxicity and biocompatibility assessments in mouse fibroblasts demonstrated that the hydrogel supports cell proliferation without inducing toxicity, and exhibited good blood compatibility (hemolysis rate < 2.5 %). In a mouse wrinkle model, the hydrogel exhibited a favorable safety profile, elicited no inflammatory response, promoted collagen synthesis, and demonstrated prolonged in vivo retention. These findings highlight the Sericin/Nano-hydroxyapatite hydrogel as a promising dermal filler with superior mechanical properties and collagen-regenerating potential.