Engineered collagen/PLLA composite fillers to induce rapid and long-term collagen regeneration

. Compared to the single collagen and PLLA microspheres, the Col@PLLA composite fillers showed significant collagen regeneration after injecting for 5 days. The regenerated type III and type I collagens of Col@PLLA maintained high levels after 4 months post-implantation. The inflammation response further validated the regenerative mechanism and long-lasting potential of this product. The Col@PLLA fillers achieved a significant enhancement in collagen regeneration.