Investigation On Preparation Of PLGA-PLGA/BG Bilayer Microsphere Scaffold

Cartilage diseases is common in department of orthopaedics and it is very common that bone and cartilage defect need to be repaired at the same time in the clinic treatment. Consequently, single tissue-engineered bone or cartilage can not fulfill the requirement. With the development of tissue engineering, new method can be used for the bone and cartilage defect. On the basis of reviewed the literature, we concluded that a lot of research demonstrate the long-term outcome will last until the sub chondralbone be repaired and the whole architecture and composite be restored.In this study, we describe a novel biodegradable scaffolds by utilizing polymer microspheres as the building blocks for scaffold formation. This scaffold consisted of two distinct yet continuous phases, one is composed by Poly(L,D-lactic-co-glycolic acid) (PLGA) microspheres,one is composed by PLGA/Bioglass(BG) microspheres. This saffold can be used for cartilage and bone repair. In the first place, PLGA microspheres with the diameter of 80~700μm were prepared by a solvent evaporation method. The micospheres'diameter increased with the increase of the PLGA concentration . Increaseing the Stirring rate from 200 r/min to 400r/min do not effect obviously on microspheres'size; different surfactants significantly impact the Surface morphology of microspheres. In the second place, in order to prepare microsphere-scaffold with the function of drug delivery and enhance the application value of microsphere-scaffold, PLGA microspheres and PLGA / BG microspheres were loaded with glucosamine and bovine serum albumin respectively. This paper discussed the impact of different processes on the drug loading and encapsulation efficiency. Studies show that the solvent evaporation method with solid drug filling can significantly improve the encapsulation efficiency of glucosamine, the encapsulation efficiency increased form 0% to 50%, pore-forming agent can be used to prepare microspheres which have structure similar to sponge, the drug-load quantity is 6% and the burst release was 11.4% when soake microspheres in the BSA solution.On that basis, the scaffold was fabricated with the help of micro-wave. The scaffold materials connected with the pore structure, porosity can be regulated from about 45 % to 55 % by the adjustment of particle size. We can also regulate pore structure by the adjustment of particle size. At the same time,we discuss how the adding amount of solvent effects the appearance and the bonding conditions of the scaffold. this paper also studied the degradation of scaffold materials. We found that, in 30 days, the degradation of scaffold materials was slow. 30 days later, the degradation of scaffold materials speed, and pH value also decreased.