Osteoconductivity and Biodegradability of Collagen Scaffold Coated with Nano-β-TCP and Fibroblast Growth Factor 2

Nanoparticle bioceramics have become anticipated for biomedical applications. Highly bioactive and biodegradable scaffolds would be developed using nanoparticles of β-tricalcium phosphate (β-TCP). We prepared collagen scaffolds coated by nano-β-TCP and fibroblast growth factor 2 (FGF2) and evaluated the effects on new bone augmentation and biodegradation. The collagen sponge was coated with the nano-TCP dispersion and freeze-dried. Scaffold was characterized by SEM, TEM, XRD, compressive testing and cell seeding. Subsequently, the nano-β-TCP/collagen scaffold, collagen sponge, and each material loaded with FGF2 were implanted on rat cranial bone. As a control, no implantation was performed. Nano-TCP particles were found to be attached to the fibers of the collagen sponge by SEM and TEM observations. Scaffold coated with nano-TCP showed higher compressive strength and cytocompatibility. In histological evaluations at 10 days, inflammatory cells were rarely seen around the residual scaffold, suggesting that the nano-TCP material possesses good tissue compatibility. At 35 days, bone augmentation and scaffold degradation in histological samples receiving nano-β-TCP scaffold were significantly greater than those in the control. By loading of FGF2, advanced bone formation is facilitated, indicating that a combination with FGF2 would be effective for bone tissue engineering

Comparative study of bioactivity of collagen scaffolds coated with graphene oxide and reduced graphene oxide

Graphene oxide (GO) is a single layer carbon sheet with a thickness of less than 1 nm. GO has good dispersibility due to surface modifications with numerous functional groups. Reduced graphene oxide (RGO) is produced via the reduction of GO, and has lower dispersibility. We examined the bioactivity of GO and RGO films, and collagen scaffolds coated with GO and RGO. METHODS:GO and RGO films were fabricated on a culture dish. Some GO films were chemically reduced using either ascorbic acid or sodium hydrosulfite solution, resulting in preparation of RGO films. The biological properties of each film were evaluated by scanning electron microscopy (SEM), atomic force microscopy, calcium adsorption tests, and MC3T3-E1 cell seeding. Subsequently, GO- and RGO-coated collagen scaffolds were prepared and characterized by SEM and compression tests. Each scaffold was implanted into subcutaneous tissue on the backs of rats. Measurements of DNA content and cell ingrowth areas of implanted scaffolds were performed 10 days post-surgery. RESULTS: The results show that GO and RGO possess different biological properties. Calcium adsorption and alkaline phosphatase activity were strongly enhanced by RGO, suggesting that RGO is effective for osteogenic differentiation. SEM showed that RGO-modified collagen scaffolds have rough, irregular surfaces. The compressive strengths of GO- and RGO-coated scaffolds were approximately 1.7-fold and 2.7-fold greater, respectively, when compared with the non-coated scaffold. Tissue ingrowth rate was 39% in RGO-coated scaffolds, as compared to 20% in the GO-coated scaffold and 16% in the non-coated scaffold. CONCLUSION: In summary, these results suggest that GO and RGO coatings provide different biological properties to collagen scaffolds, and that RGO-coated scaffolds are more bioactive than GO-coated scaffolds

Bone augmentation in rat by highly porous β-TCP scaffolds with different open-cell sizes in combination with fibroblast growth factor-2

We prepared highly porous beta-tricalcium phosphate (β-TCP) scaffolds with different open-cell structure sizes. The aim of this study was to examine whether the open-cell size of the scaffold affected osteoinduction in combination with fibroblast growth factor-2 (FGF2) in rats. Polyurethane foam was immersed in β-TCP slurry and sintered in a furnace. Porous β-TCP scaffolds were prepared in three cell sizes (0.6, 0.4 and 0.3 mm) and characterized. Subsequently, each scaffold with FGF2 was implanted to rat cranial bone. Histomorphometric analyses were taken at 35 days post-surgery. The results showed that each β-TCP scaffold exhibited fully interconnected porosity, and frequently allowed bone tissue ingrowth. The 0.4-mm cell sized scaffold significantly promoted bone augmentation compared to the 0.3-mm type. Resorption of the β-TCP scaffold of 0.4-mm cell size was frequently accelerated. In conclusion, FGF2-loaded β-TCP scaffolds with 0.4-mm cell size would be effective for bone tissue engineering

Bone augmentation using a highly porous PLGA/β-TCP scaffold containing fibroblast growth factor-2

Background and objective: β-tricalcium phosphate (β-TCP), a bio-absorbable ceramic, facilitates bone conductivity. We constructed a highly porous three dimensional scaffold using β-TCP for bone tissue engineering and coated it with co-poly lactic acid/glycolic acid (PLGA) to improve the mechanical strength and biological performance. The aim of this study was to examine the effect of the implantation of the PLGA/β-TCP scaffold loaded with fibroblast growth factor-2 (FGF2) on bone augmentation. Material and methods: The β-TCP scaffold was fabricated by the replica method using polyurethane foam, then coated with PLGA. The PLGA/β-TCP scaffold was characterized by SEM, TEM, XRD, compressive testing, cell culture, and a subcutaneous implant test. Subsequently, a bone forming test was performed using fifty two rats. The β-TCP scaffold, PLGA-coated scaffold, and β-TCP scaffold and PLGA-coated scaffolds loaded with FGF2, were implanted into rat cranial bone. Histological observations were made at 10 and 35 days post-surgery. Results: SEM and TEM observations showed a thin PLGA layer on the β-TCP particles after coating. High porosity of the scaffold was exhibited after PLGA coating (> 90%), and the compressive strength of the PLGA/β-TCP scaffold was 6-fold greater than the non-coated scaffold. Good biocompatibility of the PLGA/β-TCP scaffold was found in the culture and implant tests. Histological samples obtained following implantation of PLGA/β-TCP scaffold loaded with FGF2 showed significant bone augmentation. Conclusion: The PLGA coating improved the mechanical strength of β-TCP scaffolds while maintaining high porosity and tissue compatibility. PLGA/β-TCP scaffolds in combination with FGF2 are bioeffective for bone augmentation