Polycaprolactone/chitosan Polymer Blends For Cartilage Tissue Engineering Scaffold Research

The biocompatibility biomaterials play a important role in the cartilage reconstruction as it's good for cell attachment and growth. Biological materials'toxicity to cells , adhesion properties of cells , cell proliferation on the materials are three indicator of the biocompatibility of materials. Polycaprolactone (PCL) and chitosan (CS) both have good biocompatibility, biodegradability and non-toxic to cells, and have a wide range of biomedical applications. PCL molecular chain arranged and folded to form the amorphous areas. These chains interlaced with each other forms the semi-crystalline linear polymer, because of this structure, PCL has a good compression performance, mechanical relaxation, creep properties and has good flexibility. Due to the nature of semi-crystalline, PCL is highly hydrophobic. Chitosan and its derivatives possess renewable nature, biocompatibility, as well as the structure of variety of active groups, including amio, acetyl, and hydroxyl groups, which have good performance on biocompatibility and highly hydrophilic. However, it's lack of the basic mechanics of mechanical properties. Using the high concentration of acetic acid as the common solvent to make the PCL/CS form a homogeneous materials. Hybrid materials have been mixed to enhance the mechanical properties, the dates show that mechanical properties of hybrid materials is significantly improved , especially the PCL mass ratio of 80%. There is no significant difference between the chitosan and PCL mass ratio of 50%, when the cells attached on them. Chondrocytes'proliferation is significantly proved at the cell culture time 7d, 14d, 28d. The pure chitosan can not maintain its high porosity of the 3-D pore structure after immersion in PBS for 2 weeks, the collapse structure prevents the cells exchange substances with the outside environment. We use particle leaching method to fabricating porous scaffolds with the NaCl particle diameter about 200-300μm. Pore structure of the scaffolds was analyzed by SEM , the high porosity of the scaffolds play a positive role in cell adhesion behavior, and also in cell proliferation. In this study, MTT, toluidine blue, H & E staining has been used as evaluation methods.