To obtain an aqueous polymer system with good antibacterial properties, a series of gemini waterborne polyurethanes （GWPU） were designed and synthesized using isophorone diisocyanate, polyoxytetramethylene glycol, poly（ethylene glycol）, L-lysine and a novel L-lysine-derivatized diamine containing gemini quaternary ammonium salt （EG12） without any other organic agent involved in the whole synthetic process. EG12 was first synthesized and characterized with proton nuclear mag- netic resonance spectra and mass spectra. The antibacterial activities of EG12 and GWPU were evaluated by quanti- fying the minimal inhibitory concentration. The results indicated that the gemini quaternary ammonium chain extender EG12 and GWPU showed excellent antibacterial activity against a broad spectrum of gram-positive and gram-negative bacteria. This work provides a new and facile approach to prepare novel antibacterial materials, which could be applied as coatings in various fields to prevent microbial contamination.
Yi ZhangYifan LiJiehua LiYunlong GaoHong TanKunjie WangJianshu LiQiang Fu
To better investigate the degradation and biocompatibility of waterborne biodegradable polyurethanes for tissue engineering, a series of new waterborne biodegradable polyurethanes （PEGPUs） with low degree of crosslinking was synthesized using IPDI, BDO and L-lysine as hard segments, PCL and PEG as soft segment. The bulk structures and properties of the prepared polyurethanes were characterized by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimetry （DSC）, tensile mechanical tests and water contact angle （WCA） measurements. The degree of microphase separation was slightly improved because of the lowered crosslinking degree of these PEGPUs in comparison with the high cross-linking degree samples, leading to good mechanical properties, as indicated by DSC and stress-strain data. Moreover, biodegradability of the polyurethanes was evaluated in phosphate buffer solutions （PBS） under different pH values and enzymatic solution at pH 7.4 through weight loss monitoring. The results suggested that the degradation of these PEGPUs was closely related to their bulk and surface properties. And the degradation products didn＇t show apparent inhibition effect against fibroblasts in vitro. These studies demonstrated that the waterborne biodegradable polyurethanes could find potential use in soft tissue engineering and tissue regeneration.
Ni-jia SongXia JiangJie-hua LiYong PangJian-shu LiHong TanQiang Fu
