Polyethyleneimine (PEI) was used to create active groups on the poly (lactide-co-glycolide)/nano-hydroxyapatite (PLGA/NHA) surface and Arg-Gly-Asp (RGD) was grafted on the active groups and novel PLGA/NHA 2-D membranes and 3D scaffolds modified with RGD were obtained. X-ray photoelectron spectrum (XPS) results show that sulfur displays only on the modified surface. The RGD-modified PLGA/NHA materials also have much lower static water contact angle and much higher water-absorption ability, which shows that after chemical treatment, the modified materials show better hydrophilic properties. Atomic force microscope (AFM) shows that after surface modification, the surface morphology of PLGA is greatly changed. All these results indicate that RGD peptide has successfully grafted on the surface of PLGA. Rabbit bone marrow stromal cells (MSCs) were seeded in the 2D membranes and 3D scaffolds materials. The influences of the RGD on the cell attachment, growth and differentiation, and proliferation on the different materials were studied. The modified scaffolds were implanted into rabbits to observe preliminary application in regeneration of mandibular defect. The PLGA/NHA-RGD presents better results in bone regeneration in rabbit mandibular defect. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

In resent years, poly(lactic acid) (PLA) foams have been studied to replace traditional polymer foams in packaging field. Unfortunately, the foaming rate of PLA is low due to its low viscosity and elasticity. To overcome these shortcomings, a biodegradable polyester, poly(butylene adipate-co-terephthalate) (PBAT) was blended with PLA to improve melt properties of PLA. Additionally, maleic anhydride (MAH) and 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (L101) were added to improve the compatibility of PLA with PBAT. The blends were extruded into foams using a twin-screw extruder. The properties of extrudates were characterized by FTIR, DSC, ARES Rheometer, and SEM. The results show that complex viscosity of PLA/PBAT blend increases by nearly 100% compared with pure PLA. Meanwhile, cell structure of foamed PLA/PBAT blend is much larger and the distribution of cells is more homogenous. The foaming rate of PLA/PBAT blend foams is raised by nearly 50% than that of pure PLA foams. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Nonwoven, biodegradable membranes fabricated by electrospinning have recently attracted a great deal of attention for biomedical applications. In this study, microporous, nonwoven membranes of poly(L-lactide) and its copolymers and blends were fabricated through electrospinning. The structures and morphologies of the electrospun membranes were investigated with scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction. Different polymer membranes, incorporated with carmofur, were fabricated, and their drug release profiles were investigated. Scanning electron microscopy images showed that the fiber diameters were down to the nanometer range. The diameters and morphologies of thenanofibers depended on processing parameters such as the solution properties (concentration and polymer molecular weight), applied electric voltage, solution feeding rate, and needle diameter. Differential scanning calorimetry showed that the crystallinity of the electrospun membranes was lower than that of the cast film. For all the membranes incorporated with the drug, there was a burst release in the first 10 h of incubation in phosphate-buffered saline at 37°C. Poly(glycolide-co-lactide) membranes showed faster and more complete drug release than poly(L-lactide), and this could be attributed to its faster degradation. The incorporation of polylactide–poly(ethylene glycol) could shorten the drug release time. A combination of suitable degradable biomaterials with an appropriate electrospinning process could be useful in the fabrication of a new kind of membrane suitable for different biomedical applications such as tissue engineering and drug delivery. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008