Synthesis and characterization of tannin grafted polycaprolactone.

Tannin and biodegradable polyester have attracted increasing interest for biomedical applications. To improve their compatibility, a novel tannin grafted polycaprolactone (TA-g-PCL) has been synthesized via ring-opening polymerization reaction. The structure of the product is characterized with FTIR, (1)H NMR and GPC. GPC results show that the experimental molecular weight is far less than the theoretical due to complicated stereo structure and large steric hindrance of tannic molecule, but the polydispersity of the product is narrow. At 115.76:1 of molar ratio of CL to tannin, molecular weight of the product reaches the maximum. Thermodynamics properties and dissolubility of TA-g-PCL are closely related to its molecular weight. With PCL molecular chain grows, TA-g-PCL changes from amorphous form to crystalline structure, and its dissolubility in chloroform is also enhanced significantly.

Effect of blending HA-g-PLLA on xanthohumol-loaded PLGA fiber membrane.

Electropsun poly (lactide-co-glycolide) (PLGA) fiber membrane loaded xanthohumol (XN) has been developed using a co-solvent system of chloroform and dimethylformamide. To enhance its biological functionality as bone tissue engineering scaffolds, 5wt% hydroxyapatite grafted poly (l-lactic acid) (HA-g-PLLA) is blended into the spinning solution. The purpose of the present work is to disclose the effect of blending HA-g-PLLA on the corresponding properties of the medicated fiber membrane including morphology, thermodynamics, wettability, drug release, mechanics as well as cytotoxicity. XN and HA-g-PLLA can be well blended with PLGA to make fibers. Blending HA-g-PLLA not only turns amorphous XN/PLGA fiber membrane into crystal structure, but also changes the membranous wettability. Various medicated membranes exhibit the sustained release profiles. Drug release rate of the ternary membrane with HA-g-PLLA is slower compared to the binary XN/PLGA, and for the ternary membrane, the drug release accelerates with increasing XN content. A model is proposed to account for the drug release process. Tensile testing shows that at 10% of XN, the comprehensive mechanics of the ternary is preferable to the binary. At the same time, these fiber membranes are no cytotoxicity.