In vitro effectiveness of microspheres based on silk sericin and Chlorella vulgaris or Arthrospira platensis for wound healing applications

Some natural compounds have recently been widely employed in wound healingapplications due to their biological properties. One such compound is sericin, which is producedby Bombix mori, while active polyphenols, polysaccharides and proteins are synthetized byChlorella vulgaris and Arthrospira platensis microalgae. Our hypothesis was that sericin, as an optimalbioactive polymeric carrier for microencapsulation process, could also improve the regenerative effectof the microalgae. A solvent-free extraction method and spray drying technique were combined toobtain five formulations, based on algal extracts (C. vulgaris and A. platensis, Chl and Art, respectively)or silk sericin (Ser) or their mixtures (Chl-Ser and Art-Ser). The spray drying was a suitable methodto produce microspheres with similar dimensions, characterized by collapsed morphology witha rough surface. Art and Art-Ser showed higher antioxidant properties than other formulations.All microspheres resulted in cytocompatibility on fibroblasts until 1.25 mg/mL and promoted cellmigration and the complete wound closure; this positive effect was further highlighted after treatmentwith Art and Art-Ser. To our surprize the combination of sericin to Art did not improve the microalgaeextract efficacy, at least in our experimental conditions.