High-temperature emulsification coupled with low-temperature gelation for fabrication of agarose microsphere implants with well-controlled size for skin tissue enhancement

Soft tissue deficiencies profoundly impact the daily lives, and mental well-being of patients. Microspheres facilitate collagen synthesis by establishing a conducive environment for fibroblast growth. Existing synthetic polymer microspheres are typically prepared through emulsification and cross-linking at normal temperatures. However, residues of cross-linking agents can adversely affect biocompatibility, thereby limiting their biomedical applications. Agarose has garnered significant attention owing to its biodegradability and excellent biocompatibility. We have for the first time developed high-temperature emulsification coupled with low-temperature gelation for fabrication of agarose microsphere implants with well-controlled size for skin tissue enhancement. The agarose microspheres exhibited favorable sphericity and dispersion, possessing a uniform particle size with an average diameter of 37.24 μm. Furthermore, the microspheres demonstrated commendable injectability and biodegradability. Additionally, the implants displayed remarkable biocompatibility, effectively promoting the proliferation of human foreskin fibroblast-1 (HFF-1) cells. The microspheres exhibited no systemic toxicity and induced no hemolytic or thermogenic reactions. In photoaged mice skin models, the agarose microspheres augmented dermal density, and enhanced skin elasticity. The microspheres showed the capacity to stimulate the regeneration of collagen fibers. The agarose microspheres offer a novel avenue for soft tissue filling and hold significance in the field of tissue engineering and skin regeneration.