Chemical Modification Of Sodium Alginate And Preparation And Properties Of Electrospun Fiber Membrane

Sodium alginate is a kind of natural anionic polysaccharide which has been widely studied and used in biomedical fields such as tissue engineering and drug delivery.However,it has some problems such as poor stability,insufficient water resistance,and inability to support hydrophobic drugs,so it often needs to be modified in the application process.The hydrophilic and hydrophobic properties of sodium alginate can be changed by chemical modification and new properties can be given.Electrospinning is an effective technology for the preparation of nanofibers with high specific surface area and large porosity.The preparation of nanofibers from sodium alginate can play a great role in biomedicine,but there are still some challenges in electrospinning due to the rigidity of sodium alginate.In order to improve the stability of sodium alginate fiber membrane,it needs to be crosslinked,but the commonly used Ca²⁺crosslinking and glutaraldehyde crosslinking in common use have some disadvantages.In this contribution,based on the modification of sodium alginate carboxyl group,the photocrosslinking group was introduced to improve the electrospinning performance of sodium alginate,and the sodium alginate nanofiber membrane was prepared.The stability of the fiber membrane was improved by photocrosslinking which could be quickly crosslinked in situ under physiological conditions;The hydroxyl group of sodium alginate was modified and the long-chain molecules were grafted into an organic solvent system by the homogeneous reaction.The solution properties and solubilization effect of sodium alginate on hydrophobic substances were studied.The main contents of the study were as follows:1.The AEMA was successfully grafted onto the carboxyl group of sodium alginate by EDC/NHS activation method,and a photocrosslinked double bond was introduced.The modification will reduce the hydrogen bond density of sodium alginate and improve chain flexibility.Under the conditions of the spinning voltage of 25 kV,the flow rate of 8μL/min,receiving distance of 18 cm,and spinning temperature of 40℃,the fiber membrane with good morphology was prepared by blending sodium alginate with PEO.The fiber membrane after double crosslinking has good mechanical properties and stability2.SA-TBA,which can be completely dissolved in organic solvents,was prepared by formic acid acidification.The amphiphilic SA-C11 grafted with undecenoic acid was synthesized by modifying the hydroxyl group of sodium alginate in the organic solvent.When the concentration of SA-C11 is greater than the critical association concentration（CAC）of 5.5 mg/m L,the hydrophobic association microregion between molecules will be generated.SA-C11 has obvious solubilization effect on hydrophobic drugs and dyes.