Studies On The Preparation And Properties Of ACF/PLGA Scaffolds For Bone Tissue Engineering

A novel activated carbon fiber/poly (lactic-co-glycolic acid) (ACF/PLGA) bone tissue engineering composite scaffold was successfully prepared, which can enhance the hydrophilicity, cell adhesion and histocompatibility. The details are as follows:(1) ACF with high strength and high adsorbability was developed. Rayon-based carbon fiber was firstly impregnated with O.lmol/L NaH2PO4 solution, then, activated at 800,850 and 900℃, respectively. It was found that activation temperature has a significantly impact on the carbon yield, density, surface topography, specific surface area, fiber tensile strength and other properties of ACF. With the increasement of activation temperature, yield, density and fiber tensile strength decreased, but the numbers of macropores on fiber suface, and specific surface area increased. The samples, which were activated at 900℃, possessed better comprehensive properties in terms of macropore size distribution and specific surface area. ACF activated at 900℃was further treated by chemical and plasma methods, in order to graft more hydrophilic groups, such as-COOH and-OH.(2) The influence of porosity of scaffold on structure and biological properties was studied. PLGA scaffolds with porosities of 55±2%,65±2% and 75±2% were prepared respectively by solvent casting/particulate leaching method. It was found that porosity of scaffold has obviously influence on morphology, compressive strength and degradation rate, but has limited influence on the distribution of pore size. With the increasement of porosity, the compressive strength decreased and degradation rate increased. It was observed that the scaffolds with porosity of 75±2% were much more helpful for cell proliferation, when mouse fibroblast (L929) was cultured on the scaffolds after 1,3,5 and 7 days. SEM observed that L929 adhered well on the scaffolds after mouse fibroblast (L929) was cultured on the scaffolds for 1 day. Furthermore, HE sections showed that tissue around scaffolds were immunoreactive at low level, when the PLGA scaffolds have implanted to subcutaneous tissue of mice for a month. Conclusively, high porosity of PLGA scaffolds were suitable for cell proliferation.(3) The influences of doping ACF on structure and biological properties of composite scaffolds were also discussed. ACF/PLGA composite scaffolds, by doping ACF with surface treatment into PLGA, were prepared by solvent casting/particulate leaching method. The mass fractions of ACF were 0%,2.75% and 8.26% respectively. It was found that the mass fracture of ACF had influenced on morphology, compressive strength, hydrophilicity and pore size distribution of scaffolds. The hydrophilicity increased, pore size distribution trends to rationalization, and the compressive strength decreased, with the content of ACF increasing. It was also observed that L929 cells adhered better on the ACF/PLGA scaffolds after the cells was cultured on the scaffolds for one day, compared with pure PLGA scaffolds. HE sections showed that tissue around ACF/PLGA scaffolds were immunoreactive at low level, and the tissue grew in the composite scaffolds was more uniform, when the scaffolds had implanted to subcutaneous tissue of mice for a month. In general, ACF/PLGA composite scaffolds are better than PLGA scaffolds.ACF/PLGA composite scaffolds were prepared by doping ACF into PLGA. The novel ACF/PLGA scaffolds possessed good hydrophilicity, cell adhesion and histocompatibility. Thus, the scaffolds will have the potential for further applications in the bone tissue engineering field.