A novel biomimetic nanofibrous heparin/gelatin scaffold with sustained-release recombinant human bone morphogenetic protein-2：preparation and characterization / 中国组织工程研究

ABSTRACT

BACKGROUND:Bionic structure is one of the most important goals of scaffold design in tissue engineering. However, the majority of the bionic scaffolds do not have the capacity of sustained release of growth factors. OBJECTIVE:To fabricate a novel biomimetic nanofibrous heparin/gelatin scaffold and investigate the characterization of the scaffolds including the microstructure, the mechanical strength andin vitro recombinant human bone morphogenetic protein-2 (rhBMP-2) release. METHODS:Heparin-conjugated gelatin was prepared by chemical crosslinking and mixed with gelatin at different ratios. Nanofibrous composite scaffolds with different ratios of heparin-conjugated gelatin (0, 20% and 40%) were fabricated by using a thermaly induced phase separation combined with particle leaching technique. The amount of conjugated heparin in the scaffolds, scaffold microstructures and mechanical strength were detected and observed. The release kinetics of rhBMP-2 from the scaffolds with different concentrations of heparin conjugated gelatin was detected using ELISA method. RESULTS AND CONCLUSION:The composite scaffolds possessed abundant porosities, good mechanical properties, and biomimetic nano-structures. The macroporous size was 250-420 μm. When the ratio of heparin-conjugated gelatin was 0, 20% and 40%, the content of heparin in the scaffolds was 0, (12.82±2.49) and (25.08±3.69) mg/g, respectively, with significant differences; the elastic modulus of the composite scaffolds was (299±38), (286±40) and (236±33) kPa, respectively, with insignificant differences (P > 0.05). With the increase in the content of heparin-conjugated gelatin, the rhBMP-2 adsorption capacity of the nanofibrous heparin/gelatin scaffold is improved, thereby significantly reducing the burst release of rhBMP-2 and prolonging the releasing time.