title: Biomimetic nanofibrous gelatin/apatite composite scaffolds for bone tissue engineering.
abstract: Mimicking certain features (e.g. nanoscale topography and biological cues) of natural extracellular matrix (ECM) is advantageous for the successful regeneration of damaged tissue. In this study, nanofibrous gelatin/apatite (NF-gelatin/apatite) composite scaffolds have been fabricated to mimic both the physical architecture and chemical composition of natural bone ECM. A thermally induced phase separation (TIPS) technique was developed to prepare nanofibrous gelatin (NF-gelatin) matrix. The NF-gelatin matrix mimicked natural collagen fibers and had an average fiber diameter of about 150nm. By integrating the TIPS method with porogen leaching, three-dimensional NF-gelatin scaffolds with well-defined macropores were fabricated. In comparison to Gelfoam (a commercial gelatin foam) with similar pore size and porosity, the NF-gelatin scaffolds exhibited a much higher surface area and mechanical strength. The surface area and compressive modulus of NF-gelatin scaffolds were more than 700 times and 10 times higher than that of Gelfoam, respectively. The NF-gelatin scaffolds also showed excellent biocompatibility and mechanical stability. To further enhance pre-osteoblast cell differentiation as well as improving mechanical strength, bone-like apatite particles (<2microm) were incorporated onto the surface of NF-gelatin scaffolds via a simulated body fluid (SBF) incubation process. The NF-gelatin/apatite scaffolds 5 days after SBF treatment showed significantly higher mechanical strength than NF-gelatin scaffolds 5 days after SBF treatment. Furthermore, the incorporated apatite in the NF-gelatin/apatite composite scaffold enhanced the osteogenic differentiation. The expression of BSP and OCN in the osteoblast-(NF-gelatin/apatite composite) constructs was about 5 times and 2 times higher than in the osteoblast-(NF-gelatin) constructs 4 weeks after cell culture. The biomimetic NF-gelatin/apatite scaffolds are, therefore, excellent for bone tissue engineering.
authors.affiliation: Department of Biological and Materials Sciences, University of Michigan, Ann Arbor, MI 48109-1078, USA.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.forename: Laura A
authors.initials: LA
authors.lastname: Smith
authors.forename: Jiang
authors.initials: J
authors.lastname: Hu
authors.forename: Peter X
authors.initials: PX
authors.lastname: Ma
mesh_terms: D000818:Animals; D001031:Apatites / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry*; D001842:Bone and Bones; D002448:Cell Adhesion; D002460:Cell Line; D049109:Cell Proliferation; D005780:Gelatin / Q000737:chemistry* / Q000648:ultrastructure; D051379:Mice; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D001031:Apatites; D005780:Gelatin