Electrospun bioactive mats enriched with Ca-polyphosphate/retinol nanospheres as potential wound dressing

Background While electrospun materials have been frequently used in tissue engineering no wound dressings exist that significantly improved wound healing effectively. Methods We succeeded to fabricate three-dimensional (3D) electrospun poly(D,l-lactide) (PLA) fiber mats into which nanospheres, formed from amorphous calcium polyphosphate (polyP) nanoparticles (NP) and encapsulated retinol ("retinol/aCa-polyP-NS" nanospheres [NS]), had been incorporated. Results Experiments with MC3T3-E1 cells revealed that co-incubation of the cells with Ca-polyP together with retinol (or incubation with retinol/aCa-polyP-NS) resulted in a significant synergistic effect on cell growth compared with particle-free polyP complexed with Ca2+ or amorphous Ca-polyP NPs and retinol alone. Incubation of the cells in the presence of the retinol/aCa-polyP NSs also caused a significant increase of the expression levels of the genes encoding for the fatty acid binding protein 4 (FABP4), as well as of the genes encoding for leptin and the leptin receptor. In contrast, the single components, soluble Na-polyP, complexed to Ca2+, or retinol-free aCa-polyP NPs, and retinol, had no significant effect on the expression of these genes. Conclusions These results indicate that the PLA fibers, supplemented with aCa-polyP-NP or retinol/aCa-polyP-NS, elicit morphogenetic activity, suggesting that these fiber mats, along with the antibacterial effect of polyP, have a beneficial potential as wound dressings combining antimicrobial and regenerative (wound healing) properties. General significance The PLA-based fiber mats, containing retinol and polyP nanoparticles, provide promising bioactive meshes that are urgently needed as dressings for chronic wounds.