摘要
The motive of this work was to provide an inexpensive potential wound dressing using chitosan lactate (LCH) which was synthesized by the grafting lactic acid onto the amino groups in chitosan (CH) without a catalyst. The XRD and 13CNMR results demonstrated that the grafting by lactic acid took place at C2 site in CH, leading to the destruction of the regularity of the packing in the original CH chains and formation of the amorphous CH salts. The unique device was developed in our experiments which could yield an approximately vertical thermal gradient, forming the uniformly vertical pores in LCH sponges. TEM images revealed that both TBA and LCH concentration affected the micro-structure of the sponges, although they worked via different mechanisms. In the water suction experiments, the capillary coefficient Ks was introduced to evaluate the structure-function relationship. The positive or negative influence of LCH, TBA and porosity on Ks clearly stood out when their relationships were plotted graphically. The in vitro biocompatibility of LCH sponges was evaluated. The results obtained indicated that LCH sponges exhibited bio-safety at lower concentration (25%) during short time (1 day). However, highly concentrated extraction showed a serious toxic effect on both HSF and HaCaT cells. The release kinetics for hydrophilic and hydrophobic drugs with different formulation sponges was determined in in vitro release experiments. The contribution of the drug diffusion, matrix erosion and microstructure of porous materials must be taken into account on the release mechanism. The method and the structure described in present paper provided a starting point for the design and fabrication of a family of chitosan derivatives based porous materials with potentially broad
The motive of this work was to provide an inexpensive potential wound dressing using chitosan lactate (LCH) which was synthesized by the grafting lactic acid onto the amino groups in chitosan (CH) without a catalyst. The XRD and 13CNMR results demonstrated that the grafting by lactic acid took place at C2 site in CH, leading to the destruction of the regularity of the packing in the original CH chains and formation of the amorphous CH salts. The unique device was developed in our experiments which could yield an approximately vertical thermal gradient, forming the uniformly vertical pores in LCH sponges. TEM images revealed that both TBA and LCH concentration affected the micro-structure of the sponges, although they worked via different mechanisms. In the water suction experiments, the capillary coefficient Ks was introduced to evaluate the structure-function relationship. The positive or negative influence of LCH, TBA and porosity on Ks clearly stood out when their relationships were plotted graphically. The in vitro biocompatibility of LCH sponges was evaluated. The results obtained indicated that LCH sponges exhibited bio-safety at lower concentration (25%) during short time (1 day). However, highly concentrated extraction showed a serious toxic effect on both HSF and HaCaT cells. The release kinetics for hydrophilic and hydrophobic drugs with different formulation sponges was determined in in vitro release experiments. The contribution of the drug diffusion, matrix erosion and microstructure of porous materials must be taken into account on the release mechanism. The method and the structure described in present paper provided a starting point for the design and fabrication of a family of chitosan derivatives based porous materials with potentially broad applicability
