Synthesis and properties of waterborne polyurethane hydrogels for wound healing dressings

To accomplish ideal wound healing dressing, a series of waterborne polyurethane (WBPU) hydrogels based on polyethylene glycol (PEG) were synthesized by polyaddition reaction in an emulsion system. The stable WBPU hydrogels which have remaining weight of above 85% were obtained. The effect of the soft segment (PEG) content on water absorbability of WBPU hydrogels was investigated. Water absorption % and equilibrium water content (%) of the WBPU hydrogel significantly increased in proportion to PEG content and the time of water-immersion. The maximum water absorption % and equilibrium water content (%) of WBPU hydrogels containing various PEG contents were in the range of 409-810% and 85-96%, respectively. The water vapor transmission rate of the WBPU hydrogels was found to be in the range of 1490-3118 g/m(2)/day. These results suggest that the WBPU hydrogels prepared in this study may have high potential as new wound dressing materials, which provide and maintain the adequate moist environment required to prevent scab formation and dehydration of the wound bed. By the wound healing evaluation using full-thickness rat model experiment, it was found that the wound covered with a typical WBPU hydrogel (HG-78 sample) was completely filled with new epithelium without any significant adverse reactions.