Study On The Preparation Of Antibacterial Soybean Protein Isolate Membranes By Electrospinning

Soy protein isolate(SPI)has the excellences of abundance in raw material,high nutritional value and so on.It is widely used in food packaging and biomedical realm for its better biocompatibility and biodegradability.The electrospun SPI/PEO membranes have a larger specific surface area and porosity.When used as wound dressing,the membranes have a great advantage in moisturizing,breathable and antibacterial.However,SPI has strong hydrophilic properties,which leads to poor water stability and mechanical properties and can not meet the requirements of wound dressing.In order to broaden the application of electrospun SPI/PEO membranes in the biomedical field,chemical cross-linking was used.The effects of maleic anhydride(MA)and dialdehyde chitosan(D-CTS)on the water stability,thermal stability and mechanical properties of electruspun SPI/PEO membranes were investigated.The cross-linking mechanism was also studied.At the same time,chitosan(CS)was added as an antibacterial agent,synergistically with the porous microstructure of the electrospun SPI/PEO membranes.The cross-linked SPI/PEO membranes were tested for their hydrophilicity,liquid absorption and retention,water vapor transmission rate and cytotoxicity to evaluate the possibility of using as wound dressings.The main conclusions were summarized as followed:(1)Using SPI and PEO as raw materials to prepare electrospun SPI/PEO membranes.When SPI/PEO=2:1,the fiber of the membrane is smooth and uniform.However,it has high melt-dissolving rate,poor mechanical properties,and basically does not possess antibacterial properties and can not be satisfied.The use of wound dressing requires the use of chemical cross-linking methods to modify them.(2)The preferred process for MA cross-linked SPI/PEO membranes is: 170?,10 min,8% MA.The SPI/PEO membrane has the lowest loss rate of 30.8%,and its porous microstructure can be in PBS buffer at 37? for 15 days,the maximum tensile strength and elongation at break are 2.3MPa and 9.6%,respectively.Cross-linking between SPI and MA resulted in the generation of saturated carboxylic acid groups,and a new functional group(C=O)appeared in the infrared spectrum.MA induced the amino residues of SPI arranged regularly,so small crystals with a certain orientation were formed near 21.5°.The increase of the melting temperature of SPI and PEO,and the increase of the mass ratio of ash remaining after high-temperature degradation of the SPI/PEO membrane indicated that the thermal stability of the SPI/PEO membrane was increased.Chitosan has inhibitory effects on S.aureus and E.coli,and the inhibition of the former is higher than that of the latter.(3)Sodium periodate selectively oxidized CS and introduced aldehyde groups,making it a new type of biomass-based crosslinker(D-CTS).The optimum process of D-CTS cross-linked SPI/PEO membrane is: 170?,15 min,8% D-CTS.At this time,the SPI/PEO membrane has the lowest loss rate of 31%,and its porous microstructure can be in 37? PBS buffer for 10 days,the maximum tensile strength and elongation at break are 2.19 MPa and 9.5%,respectively.SPI and D-CTS crosslinked and produced schiff base(C=N).The better liquid crystal property of C=N formed a new crystallization peak around 20.4°.The increase of the melting temperature of SPI and PEO,and the increase of the mass ratio of ash remaining after high-temperature degradation of the SPI/PEO membrane indicated that the thermal stability of the SPI/PEO membrane was increased.Compared with chitosan,D-CTS has a better antibacterial effect.(4)It was found that the membrane had higher hydrophilicity,liquid absorption rate and liquid retention rate,water vapor transmission rate and low toxicity to cells.So it has a good application prospect in the application of wound dressings.