The Preparation Of Oxidized Alginate/Chitosan Composite Hydrogel And Its Preliminary Study

Sodium alginate and chitosan are both safe and nontoxic natural polymers with good biocompatibility and biodegradability,which are widely used in biomedical fields.Driven by the electrostatic interaction,the negatively charged sodium alginate and positive chitosan can form hydrogel.Along with this line,we prepared oxidized sodium alginate/carboxymethyl chitosan hydrogel,sodium alginate/carboxymethyl chitosan/bovine serum albumin hydrogel,and further introduced nano-silver into these hydrogels,yielding the nano silver containing antibacterial hydrogels,respectively.The biomedical application of the hydrogels were preliminary investigated,and these hydrogels can be used as wound dressing.The results were as follows:1.CMC/OSA hydrogel was prepared using sodium alginate as crosslinking agent.The swelling property,rheological property and in vitro degradation of the hydrogel was investigated.The results showed that the hydrogel CMC/OSA exhibited pH sensitivity,The hydrogel shrinked at lower pH value but swelled at higher pH,which endowed the hydrogel with off-on pH sensitivity.Rheological results showed that CMC/OSA hydrogel had a relatively intact network structure with low crosslinking degree,and no crosslinked carboxymethyl chitosan aggregated into tangles.In vitro degradation test showed that CMC/OSA composite hydrogel would slowly degrade under physiological conditions.2.Water soluble CMC/OSA hydrogel was prepared by using sodium alginate as crosslinking agent.The chemical structures of CMC,OSA and composite hydrogel were characterized by FT-IR spectroscopy.The morphology of the hydrogel was observed by SEM.In vitro drug release behavior of the composite hydrogel was studied with bovine serum albumin(BSA)as the model drug.Mathematical model of drug release curve was carried out to find the optimized model of drug release.The results showed that the amino groups within CMC and dialdehyde of OSA led to the formation of chemical crosslinking based on Schiff's base reaction.The amino group of CMC and carboxyl group of OSA led to the electrostatic interaction.Based on these physical and chemical interaction,CMC/OSA composite hydrogel formed.SEM results showed that CMC/OSA composite hydrogel had a three-dimensional network structure..In vitro drug release test results suggested that CMC/OSA composite hydrogel can be used as drug carrier for with enteric targeting function.Mathematical fitting results showed that the simulated gastric fluid release curve of drug fitted the zero order model,but the simulated colonic fluid release curve fitted the R-P model.3.On the basis of the previous chapter,the broad-spectrum antimicrobial properties of n-Ag may be used to prepare water-soluble CMC/OSA/n-Ag hydrogel.The existance of n-Ag was characterized by UV-Vis.The particle morphology of n-Ag was measured by TEM.MTT assay was conducted to investigate the cell toxicity of the prepared hydrogel against L929 cell line.Meanwhile,the antibacterial property was investigated.AgNO3 has been reverted to Ag based on the examination of UV-Vis spectrum.The TEM observation showed that silver nano-particles were uniformly dispersed.The size of silver nano-particles was about 20 nm.The MTT results showed the CMC/OSA/n-Ag composite hydrogel exhibited nontoxic against L929,suggesting that the antibacterial hydrogel was biocompatible to animal cells and could be used as wound dressing.The CMC/OSA/n-Ag composite hydrogel exhibited excellent antibacterial properties to Escherichia coli and Staphylococcus aureus The antimicrobial hydrogel has great potential for the skin antimicrobial treatment.4.The HBCS/OSA/n-Ag hydrogel plast was prepared by supported OSA on medical nonwoven fabric.The hydrogel was through ?-ray sterilization after sealing in bag.The micromorphology of the hydrogel was observed by means of SEM.MTT assay was conducted to investigate the cell toxicity of the prepared hydrogel against L929 cell line.The antibacterial property was investigated.The clinical application of the HBCS/OSA/n-Ag composite hydrogel was investigated.SEM results showed that HBCS/OSA/n-Ag composite hydrogel had a three-dimensional network structure.which could lock and release water when the skin was covered with the hydrogel.The hydrogel has a good moisturizer for wound to promote healing.The MTT results showed the HBCS/OSA/n-Ag composite hydrogel exhibited nontoxic against L929,suggesting that the antibacterial hydrogel was biocompatible to animal cells and could be used as wound dressing.The HBCS/OSA/n-Ag composite hydrogel exhibited excellent antibacterial properties to Escherichia coli and Staphylococcus aureus The antimicrobial hydrogel has great potential for the skin antimicrobial treatment.The clinical studies showed the HBCS/OSA/n-Ag composite hydrogel can play an effective role in promoting for low burns.