Fabrication, Characterization And Electrochemical Mineralization Of Natural Biomaterial-Based Three-Dimensional Porous Scaffolds

In this work, three-dimensional (3-D) porous scaffolds were fabricated by using natural biopolymers. To mimic the component of natural bone, mineralized gelatin porous scaffolds were produced by an electrochemical mineralization (EM) method. The main study contents are as follows:3-D porous gelatin-hyaluronic acid (GE-HA) hybrid scaffolds were fabricated by a phase separation/freeze-drying method. The effects of both phase-separation temperature and the ratios of gelatin to HA on the porous topography and characterization of the scaffolds were investigated. SEM results suggested that the hybrid scaffolds possessed porous structures, which varied with the changes of phase-separation temperature or the ratios of gelatin to HA. FTIR results suggested that the intensity with respect to amide bands and ester band had slight increases in spectra of cross-linked GE-HA hybrid scaffolds by EDC. Moreover, the swelling ratio, in vitro degradation properties and compressive strength of the hybrid scaffolds varied as the changes of the ratios of gelatin to HA. SEM results revealed the fibroblast L929 grew well on both pure gelatin and GE-HA hybrid scaffolds with a nice morphology. The proliferation situation of L929 cells on the scaffolds were assayed by MTT. The combined results of the physicochemical and biological studies suggested that the GE/HA hybrid scaffolds exhibit good potential and biocompatibility for tissue engineering applications.Calcium phosphate coatings on 3-D natural biomaterial-based porous scaffolds were firstly produced by an electrochemical mineralization (EM) method. The effects of several elements on the topography and composition of the crystals coating on mineralized gelatin scaffolds were systematically investigated, such as mineralization time, voltage, electrolyte temperature, and sonoelectrodeposition. SEM suggested that the morphology of the mineral crystals deposited at a lower voltage (2 V) or temperature (25℃) were plate-like structure, which almost attached to the edge of the pore wall. While at the higher voltages (3 V & 5 V) or temperatures (37℃& 60℃), the deposit crystals dispersed well and were more delicate. Most especially, the crystals deposited at 60℃were needle-like, which were close to the topography of hydroxyapatite (HA) in nature bone tissue. Mass increase analysis demonstrated that higher voltage or temperature facilitated the deposition of calcium phosphate. The results of FTIR spectra studies showed the existence of carbonated apatite in mineralized gelatin scaffolds. XRD results suggested that the component of the crystals coatings deposited at a low voltage (2 V) or temperature (25℃) were almost DCPD; the crystals deposited at 60℃were almost HA, which corresponded to the SEM results; while the component of the crystals deposited at 3 V and 5 V existed no much difference, including both HA and DCPD. EDS and XPS results suggested that the deposit crystals were Ca-deficient apatite. The biological response of mouse pre-osteoblasts MC3T3-E1 on the mineralized gelatin scaffolds was superior in terms of higher proliferation and well-spread morphology. The results suggests that EM is a promising alternative for the biomineralization of 3-D polymer scaffolds, and the mineralized gelatin porous scaffolds with calcium phosphate coatings exhibit good potential and biocompatibility for bone repair.