Engineering BSA-dextran particles encapsulated bead-on-string nanofiber scaffold for tissue engineering applications

Electrospun bead-on-string nanofiber, with unique beads structure could act as reservoirs for particle drugs, is a promising fibrous structure with continuous drug release for regulating cellular functions such as cell adhesion and proliferation in tissue engineering applications. In this study, we reported on the encapsulation and sustained release of model drug (BSA) from poly (lactic-co-glycolic acid) (PLGA) beaded nanofibers loaded with BSA-dextran (B-D) particles. Smooth PLGA nanofiber scaffold with B-D particles was fabricated as a positive control. Fluorescent images of inversed florescence microscopy suggested that B-D particles tended to accumulate within beads structure of beaded nanofibers but appeared randomly along smooth nanofibers. The entrapment of B-D particles within beaded nanofibers resulted in alleviative burst release compared with smooth nanofiber and sustained release of BSA over 31 days. The holes on the surface of nanofibers caused by the release of B-D particles would accelerate the degradation of nanofibers. Tensile testing result demonstrated that beaded structure would decrease the Young's Modulus, tensile strength and elongation compared with smooth nanofibers. Cultivation of human mesenchymal stem cells on particle drugs encapsulated beaded nanofibers indicated that cells could attached and proliferated well on beaded structure nanofibers, suggesting that such beaded nanofibers with a controlled and continuous release profiles was a promising candidate scaffold for tissue regeneration.