Study On The Structure And Property Of Polycaprolactone/Chitosan Nerve Conduits

Chitosan(CS) and polycaprolactone(PCL) were blended together to form a homogeneous materials, and they were further fabricated into conduits by solvent volatilization method and immersion-dryness method sued for peripheral nerve defect. Selected chitosan solutions and polycaprolactone solutions were first mixed at various weight ratios and the homogeneous mixtures were then evaporated until the mixtures became concentrated gels. thereafter, the gels were coated onto stainless rods layer by layer to make conduits which dimensions is 20 mm in length and 2 mm in diameter and the wall thickness of the conduits is 0.5 mm.Although polycaprolactone has been widely used in tissue engineering because its good mechanical properties and excellent plasticity, its applications are frequently limited by several its drawbacks such as absence of cell recognition sites on the surface of the scaffolds, hydrophobicity, slow rate of degradation and acidic degradation productions. Chitosan has many advantages, including hydrophilicity, anti-microbial activity and cell affinity. In addition, the amino groups in backbone also make chitosan a basic characteristic. However, mechanically inferior feature of chitosan has limited its usage. On the basis of above mentioned characteristics, we blend chitosan and polycaprolactone together to form a mutually complementary potentials scaffold. In our study we fabricate five different conduits of various weight ratios (pure chitosan, CS-75/PCL-25, CS-50/PCL-50, CS-25/PCL-75, pure polycaprolactone). To study the most suitable composite conduit for repairing nerve defect, the preparation process of the composite scaffold and factors in influence conduits performance were studied; the pH value of degradation medium, weight loss of these five composite conduits were observed during the degradation in vitro.In study of the degradation speed, swelling property and mechanical properties of the composite conduits, we optimized the structure and component of conduit and had the results: we can prepare composite conduits with chitosan (Mw 500～600 KDa), polycaprolactone(Mw 5×104～8×104), the acidic acid as common solvent to prepare varied concentration solution then mixed and concentrated to form a concentrated gels. Make sure the acidic acid solvent is above 75% during the concentration process. The conduits of which wall thickness was 0.5 mm made of chitosan and polycaprolactone with weight ratio of 1:1 was perfect.