In vitro and in vivo degradation behavior of n-HA/PCL-Pluronic-PCL polyurethane composites.

Scaffolds for bone tissue engineering applications should have suitable degradability in favor of new bone ingrowth after implantation into bone defects. In this study, degradation behavior of polyurethane composites composed of triblock copolymer poly(caprolactone)-poluronic-poly(caprolactone) (PCL-Pluronic-PCL, PCFC) and nanohydroxyapatite (n-HA) was investigated. The water contact angle and water absorption were measured to reveal the effect of n-HA content on the surface wettability and swelling behavior of the n-HA/PCFC composites, respectively. The weight loss in three degradation media with pH value of 4.0, 7.4, and 9.18 was also studied accordingly. Fourier transform infrared analysis, differential scanning calorimeter, X-ray diffraction, thermal-gravimetric analysis, and scanning electron microscopy were used to investigate the change of chemical structure and micromorphology after the n-HA/PCFC composite with 30% HA was degraded for different time intervals. Meanwhile, in vivo degradation was conducted by subcutaneous implantation. The weight loss and morphology change during observation periods were also studied.

Biodegradable and thermosensitive monomethoxy poly(ethylene glycol)-poly(lactic acid) hydrogel as a barrier for prevention of post-operative abdominal adhesion.

Post-operative peritoneal adhesions are serious consequences of abdominal or pelvic surgery and cause severe bowel obstruction, chronic pelvic pain and infertility. In this study, a novel nano-hydrogel system based on a monomethoxy poly(ethylene glycol)-poly(lactic acid) (MPEG-PLA) di-block copolymer was studied for its ability to prevent abdominal adhesion in rats. The MPEG-PLA hydrogel at a concentration of 40% (w/v) was injected and was able to adhere to defect sites at body temperature. The ability of the hydrogel to inhibit adhesion of post-operative tissues was evaluated by utilizing a rat model of abdominal sidewall-cecum abrasion. It was possible to heal wounded tissue through regeneration of neo-peritoneal tissues ten days after surgery. Our data showed that this hydrogel system is equally as effective as current commercialized anti-adhesive products.

Acceleration of dermal wound healing by using electrospun curcumin-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) fibrous mats.

This study prepared a composite scaffold composed of curcumin and poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) copolymer using coelectrospinning technology. Incorporation of curcumin into the polymeric matrix had an obvious effect on the morphology and dimension of PCEC/curcumin fibers. The results of in vitro anti-oxidant tests and of the cytotoxicity assay demonstrated that the curcumin-loaded PCEC fibrous mats had significant anti-oxidant efficacy and low cytotoxicity. Curcumin could be sustainably released from the fibrous scaffolds. More importantly, in vivo efficacy in enhancing wound repair was also investigated based on a full-thickness dermal defect model for Wistar rats. The results indicated that the PCEC/curcumin fibrous mats had a significant advantage in promoting wound healing. At 21 days post-operation, the dermal defect was basically recovered to its normal condition. A percentage of wound closure reached up to 93.3 ± 5.6% compared with 76.9 ± 4.9% of the untreated control (p < 0.05). Therefore, the as-prepared PCEC/curcumin composite mats are a promising candidate for use as wound dressing.