Preparation Of Carboxymethyl Polysaccharide Nanofiber Mats And Study On Their Properties As Wound Dressings

Many acute and chronic wounds produce a large amount of exudates.If it is not removed in time,it will cause infection and hinder wound healing.The development of highly absorbent wound dressings is of great significance for wound care.Electrospun polysaccharide nanofiber mats are potential high-absorbency wound dressing materials because that natural polysaccharides are of abundant sources,low price,good biocompatibility,and biodegradability,and good hydrophilicity,and electrospun nanofiber membranes contain a lot of capillary pores,both are conducive to absorbing wound exudates.In this paper,more hydrophilic carboxymethyl anionic groups are introduced into the molecular structure of natural polysaccharides to further improve the absorption performance of electrospun polysaccharide nanofiber mats,so as to better meet the clinical needs of exudative wound treatment.The specific work content and results are as follows:In the first part of the work,hyaluronic acid is carboxymethylated and electrospun into nanofiber mats,and compared with unmodified hyaluronic acid nanofiber mats,so as to study the effect of carboxymethylation on the property of hyaluronic acid nanofiber mats.The results show that the sodium hyaluronate can be successfully carboxymethylated by treating with sodium chloroacetate under alkaline conditions.When the molar ratios of saccharide unit,sodium hydroxide,and sodium chloroacetate are 1:2:1 and 1:6:3,respectively,carboxymethyl sodium hyaluronate with carboxymethyl substitution degrees of 0.1 and 0.2 can be obtained.Using periodic acid oxidation-electrospinning-adipate dihydrazide crosslinking strategy,the original and carboxymethylated sodium hyaluronate nanofiber mats were prepared.As the degree of carboxymethylation of sodium hyaluronate gradually increased from 0 to 0.2,the average nanofiber diameter gradually decreased from 434 nm to 237 nm,the tensile strength of the nanofiber mats gradually reduced from 1.32 MPa to 0.23 MPa,the initial contact angle gradually increased from 16°to 21°,and the absorption rate of water droplets was accelerated;the absorption of simulated wound exudates by the nanofibers gradually increased from 7.0times to 10.1 times,and the absorption capacity of the inter-fiber pores gradually decreased from 29.3 times to 22.4 times.The maximum elongation rate of the sodium hyaluronate nanofiber mats is equivalent,between 20%and 30%;the water vapor permeability is equivalent,about 0.20 g/(cm~2·24h);the stability is equivalent,all of which are complete within ten days degradation.These results indicate that carboxymethylation can effectively improve the liquid absorption capacity of polysaccharide nanofibers without affecting the stretchability,air permeability,and stability of the nanofiber mats.The second part of the work is to prepare nanofiber mats from industrialized,abundant,and low-priced carboxymethyl starch as raw materials,study the relevant properties of its wound dressings,and evaluate its application potential.Carboxymethyl starch nanofiber mats were prepared by periodate oxidation-electrospinning-adipate dihydrazide crosslinking strategy.Carboxymethyl starch with an oxidation degree of 29%-60%was obtained by controlling the dosage of periodate,and the diameter of the nanofibers after electrospinning and crosslinking was 250?380 nm.The mechanical strength of the carboxymethyl starch nanofiber mats is relatively high.The wet strength is 1.9?4.3 MPa,and the maximum elongation is 20%?30%;it has good stability and only loses 8%after immersing in simulated body fluid for four weeks.About the original quality,and maintain a good nanofiber shape;high water vapor permeability,0.30?0.34 g/(cm~2·24h);strong liquid absorption capacity,a total of 10.9?17.8 times wound exudates can be absorbed.Among them,nanofibers can absorb 4.5?6.4 times,and the inter-fiber pores can absorb 6.4?11.4 times;it has excellent biocompatibility,and the cell viability in the extract is maintained above 96%.The above results indicate that the carboxymethyl starch nanofiber mats is a highly absorbent wound dressing with low cost and excellent comprehensive performance,which is expected to be used to treat highly exudative wounds.In general,this paper confirms that carboxymethylation is an effective method to improve the liquid absorption performance of electrospun polysaccharide nanofibers,which provides new ideas for the development of highly absorbent wound dressings.Further,it develops low-cost,highly absorbent.And carboxymethyl starch nanofiber mat wound dressings with excellent comprehensive performance lays the foundation for the treatment of exudative wounds.