The efficacy of basic fibroblast growth factor-loaded poly(lactic-co-glycolic acid) nanosheet for mouse wound healing.

Although human recombinant basic fibroblast growth factor (bFGF) is widely used for wound healing, daily treatment with bFGF is required because of its short half-life. An effective controlled-release system of bFGF is, therefore, desired in clinical settings. To investigate the efficacy of a bFGF-loaded nanosheet for wound healing, focusing on the controlled-release of bFGF, bFGF-loaded poly(lactic-co-glycolic acid) (PGLA) nanosheets were developed, and their in vitro release profile of bFGF and their in vivo efficacy for wound healing were examined. A polyion complex of positively charged human recombinant bFGF and negatively charged alginate was sandwiched between PLGA nanosheets (70 nm thick for each layer). The resulting bFGF-loaded nanosheet robustly adhered to silicon skin by observation using a microscratch test. bFGF was gradually and continuously released over three days in an in vitro incubation study. Treatment with the bFGF-loaded nanosheets (every 3 day for 15 days) as well as with a conventional bFGF spray effectively promoted wound healing of mouse dorsal skin defects with accelerated tissue granulation and angiogenesis, although the dose of bFGF used in the treatment with the bFGF nanosheets was approximately 1/20 of the sprayed bFGF. In conclusion, we developed a bFGF-loaded nanosheet that sustained a continuous release of bFGF over three days and effectively promoted wound healing in mice.