Improved functionalization of electrospun PLLA/gelatin scaffold by alternate soaking method for bone tissue engineering

Biomimetic biomaterials are widely being explored as scaffold for bone regeneration. In this study, we prepared poly-l-lactic acid/hydroxyapatite (PLLA/HA) and poly-l-lactic acid/gelatin/hydroxyapatite (PLLA/Gel/HA) scaffold by electrospinning of poly-l-lactic acid (PLLA) and a blend of poly-l-lactic acid/gelatin (PLLA/Gel) followed by hydroxyapatite (HA) mineralization via alternate soaking in calcium and phosphate (Ca–P) solutions. HA growth on scaffold after each soaking cycle was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The functional groups (COOsingle bond and single bondNH2) of gelatin in the PLLA/Gel scaffold facilitated the surface nucleation of HA as compared to the PLLA scaffold. Leaching study showed HA in PLLA/Gel/HA scaffold acts as binder of gelatin and eliminates use of toxic crosslinking agents. In vitro cell attachment on these scaffolds was assessed by using human osteosarcoma cells (MG-63). Cell proliferation on scaffolds was examined by MTT assay. MTT results clearly indicated that mineralized scaffolds did not inhibit the eventual cell proliferation. Alkaline phosphatase (ALP) activity of MG-63 cells was found to be the highest on PLLA/Gel/HA at day 7 compared to all other scaffolds. Complement activation study revealed minimum terminal complement complex (TCC) concentration for PLLA/Gel and PLLA/Gel/HA (617.33 and 654.13 ng/mL respectively). These results demonstrate the proficiency of PLLA/Gel/HA scaffold in better osteostimulation with lesser immune response, which attributed to synergistic role of gelatin and HA. Thus, by mimicking the natural microenvironment PLLA/Gel/HA scaffolds can become the choice of material in bone tissue engineering.