Novel Nanotechnology For The Deproteinization And Decoloration Of Lycium Barbarum L. Polysaccharides And Its Biological Function

Owing to the biocompatibility,biodegradability,non-toxicity,and some specific therapeutic activities,Lycium barbarum L.polysaccharide（LBPs）has acquired deeply research and significant attention as functional biomolecule.As the primary process of LBPs preparation,extraction and purification play an important role in the study of accurate structure-activity relationship and high-quality polysaccharide products.Therefore,ensuring the LBPs with high purity and maintaining the integrity of its natural structure is a problem worth paying attention to.However,most traditional purification methods have poor effect,complex operation and environmental pollution.The problem of difficult removal of protein and pigment in extracted polysaccharides is still expected to be solved.With high effectiveness,simple design and strong operability as well as less harmful byproducts,adsorption is commonly considered to be an economical and effective strategy to separate the targeted substance.Accordingly,adsorption shows a good prospect in the deproteinization and decoloration of LBPs.Considering the characteristics of the protein and pigment in crude LBPs,suitable nanomaterials which can be used for deproteinization and decolorization were developed,and their adsorption process and application in LBPs were explored.The main research content and results of the study are as follows:1.Preparation of the magnetic nanodeproteinizing adsorbent based on tannic acid-Fe ^IIIand its application in deproteinization of LBPsDual-functional adsorbent consisted of preferential protein adsorption coating of tannic acid-Fe ^III(TA-Fe ^III)and magnetic Fe₃O₄(Fe₃O₄@TA-Fe ^III,abbreviated as FTF NPs)was developed.The successful synthesis of FTF NPs was characterized and analyzed by the SEM,TEM,XPS and FT-IR.Then,the adsorption behavior for proteins of LBPs was evaluated by adsorption kinetics,and the changes of structure and biological activity of LBPs before and after deproteinization were explored.The results demonstrated that the adsorption process of FTF NPs for protein in LPBs could be well described by the Pseudo-second order model.Through the hydrogen bonding,electrostatic interaction and chelation,deproteinization rate could reach 96%within 10 min.Meanwhile,the molecular weight,monosaccharide composition and intracellular antioxidant activity of LBPs remained the same.Also,it exhibited widespread-use deproteinization performance to several common plant species,which provided a new technical support for deproteinization of plant polysaccharides with high efficiency.2.Preparation of graphene-based decolorizing adsorbent and its application in decolorization of LBPsNH₂-r GO was developed by one step amination and reduction of GO.The structure and components of NH₂-r GO were characterized by characterization techniques of SEM,BET,XPS and Raman.The applications in decolorization of LBP were also evaluated.The results showed that the resulted NH₂-r GO exhibited the increased surface area and abundant sp²-hybridized carbon domains.The NH₂-r GO displaying excellent selective adsorption effect on pigment of LBPs with the decoloration ratio and retention ratio of 98%and 95%,respectively,under the conditions of p H 6.3,35℃and NH₂-r GO:LBPs ratio of1:20 within 5 min.And the decolorization ratio and retention rate were higher than those of traditional H₂O₂and activated carbon adsorption methods.Meanwhile,even after five recycling operations,the NH₂-r GO still maintained high decolorization activity.Besides,the decolorizing adsorbent is also suitable for the decolorization of jujube polysaccharides and green tea polysaccharides with high ratios of>95%,exhibiting widespread-use performance towards plant polysaccharides.3.Effects of deproteinization-decolorization on the structure and activity of LBPsFTF NPs was applied to the deproteinization of LBPs,which was then decolorized by NH₂-r GO and compared with the traditional H₂O₂decolorization method.The structure of LBPs after decolorization was analyzed by SEM,AFM,HPGPC and GC,and its antioxidant activity in Caco-2 cells was evaluated.The results showed that traditional H₂O₂decolorization could change the molecular weight,monosaccharide composition and antioxidant activity of LBP.However,the advanced deproteinization and decolorization technology developed in this work will not affect the molecular weight,monosaccharide composition and proportion,as well as the antioxidant activity of LBPs.Therefore,the newly developed deproteinization and decolorization technology provides a novel,highly efficient and nondestructive method for the purification of LBPs.4.Preparation and efficacy of LBPs-enhanced nanocomposite hemostatic hydrogelWith excellent water-soluble biosafety and bioactivity,LPBs was finally applied to construct function-enhanced nano-montmorillonite-based wound repair hydrogel.The LPBs was used to exfoliate and modify of bulk MMT to get LBPs-functionalized MMT nanosheets（L-MMT NS）.Subsequently,the P-L-MMT hydrogel was prepared by mixing the L-MMT NS compositions with PVA solution,and the excellent cytocompatibility,hemocompatibility,and anti-inflammation activity were evaluated.The results showed that the obtained L-MMT NS were the well-separated nanosheets with the thickness of～1 nm.The SEM exhibited that the as-perpared P-L-MMT hydrogel showed the dispersed L-MMT NS encapsulated or embedded in the P-L-MMT hydrogel with large porous structure.Importantly,in vivo investigations demonstrated that P-L-MMT hydrogel exerts outstanding hemostasis activity on the hemorrhagin mouse liver model and obviously inhibited the excretion of TNF-α,IL-6 and IL-1β.In addition,H&E staining and the Masson’s trichrome staining confirmed the wound healing effect of the P-L-MMT hydrogel,which not only provided a new technical means for clinical application,but also provided a new idea for the development and practical application of new functions of Lycium barbarum L.polysaccharide.