Preparation Of Flammulina Velutipes Polysaccharide/Soy Proten Complex Coacervation And Its Immunity-Enhancing Effect On Macrophages

Flammulina velutipes polysaccharide（FVP）is a mixed polysaccharide with good gel properties and multiple biological activities,which is widely used in the field of functional materials.Soy protein isolate（SPI）is a commercial protein with balanced amino acids.Relevant studies found that SPI had more cell binding sites and could be used as a new type of cell gel culture substrate,but the higher gelation concentration and poor gel strength limit the application of SPI in this field.Based on the non-covalent interaction of protein/polysaccharide,the paper used FVP to modify soy protein isolate,the project studied the effects of different conditions on the complex coacervation of SPI and FVP;measured the physicochemical properties of FVP/SPI hydrogel under complex aggregation;evaluated the immune response behavior of macrophages under FVP/SPI complex hydrogel culture.Provide theoretical and technical provide a support for the application of SPI and FVP in the field of biological materials.The main findings were as follows:1、The FVP/SPI can spontaneously form complex aggregates under electrostatic interaction.The formation of FVP/SPI aggregates underwent two processes:nucleation and nucleation growth.Lower salt ion concentration(C_{Na Cl}=10,50 mmol/L)promoted the exposure of charged groups of biological macromolecules through"salting",which was beneficial to the formation of FVP/SPI aggregates,while higher salt ion concentration inhibited the formation of complex aggregations because of the surface charge of the shielded.When C_{Na Cl}=50 mmol/L,the complex aggregates exhibited the largest storage modulus.The concentration of salt ions increased the percentage ofα-helix of the aggregates.The increase in the additional amount of FVP resulted in a decrease in the critical p H of the mixed system and an increase in theβ-sheet content.SPI and FVP reached saturation at a ratio of 10:1 and15:1 and FVP/SPI aggregates had the same storage modulus value.2、The thermopolymer of FVP/SPI complexes prepared at p H 3.5 had a larger size but a smaller polydispersity index of solution,and a more complete and compact network structure.The addition of FVP could effectively improve the strength of electrostatic interaction and hydrogen bonding in the mixed system.Compared with a single SPI hydrogel,the water holding capacity of FVP/SPI complex hydrogel was significantly improved,the weakening time during the formation of FVP/SPI complex hydrogel was reduced,the storage modulus was increased.The complex hydrogel had a longer linear viscoelastic region,and as the frequency increasesd,the storage modulus increased,which showed that the addition of FVP could improve the gel properties of SPI.3、When the mixing ratio of SPI and FVP was 10:1,the swelling rate of the complex hydrogel reached the maximum（14.26%±0.23%）,and the biodegradation rate reached the minimum（0.75%±0.07%）.Under this ratio,FVP/SPI complex gel had little toxic side effects on macrophages,and the highest cell activity reached 94.86%±3.62%,which met the growth requirements of macrophages.Compared with normal cultured cells,macrophages in complex hydrogel culture had higher immune enhancement ability:the release of nitric oxide is increased by 3.5 times,the release of tumor necrosis factor-αis increased by 3.7 times,and the content of interleukin-6 is increased by 4.3 times.