| The targeted drug delivery system can selectively deliver the drug to the target lesion site and reduce the toxicity and side effects of the drug on normal tissues.With small particle size and large specific surface area,nanoparticles have high reactivity and performance.As a drug carrier,they can improve the uptake of cells at specific sites and significantly improve the efficacy of drugs.In addition,natural polymer materials have good biocompatibility and biodegradability,and the final metabolites after degradation can be absorbed by organisms.In this paper,based on the excellent properties of marine natural polysaccharides,several nano-sized delivery systems of natural polysaccharides were studied and prepared.The main research contents and results are as follows:1.Chitosan was aminated to increase the number of amino groups on the surface of chitosan,and aminated chitosan(AmCS)was obtained.After targeted modification with folic acid(FA),FA-AmCS-TPP nanoparticles were prepared by interacting with tripolyphosphate(TPP)through ion crosslinking way.Then,FA-AmCS-TPP nanoparticles were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),fourier transform infrared spectrophotometry(FT-IR),differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA).The results showed that the FA-AmCS-TPP nanoparticles with small particle size(175.2±0.99 nm),uniform dispersion(PDI=0.217)and high positive surface potential(+42.4 mV)were favorable for carrying anti-tumor drugs into tumor cells.The performance of FA-AmCS-TPP loaded curcumin was also studied,and the loading rate(EE-Cur)of curcumin and the release behavior of Cur/FA-AmCS-TPP in simulated humoral environment were investigated.The results showed that the EE-Cur of Cur/FA-AmCS-TPP was 94.26±0.91%,consisting of 0.10 g AmCS,10.0 mg FA,10.0 mg TPP and 15.0 mg curcumin.And the cumulative release rate of curcumin at 48 h was 56.2%.In addition,cell experiments showed that Cur/FA-AmCS-TPP nanoparticles had a good targeting ability for tumor cells.When curcumin concentration reached 25.0 μg/mL,the Cur/FA-AmCS-TPP nanoparticles could cause strong cytotoxicity and the survival rate of tumor cells was less than 40%.2.The composite nanoparticles(Κc-ZNPs)was prepared by the anionic polysaccharide,κ-carrageenan,and tween 80,and using a SEM,TEM and FT-IR for Κc-ZNPs have been characterized.Results show that the Kc-ZNPs exists as an approximately circular dispersed ball,in the case of zein content is constant,Κc-ZNPs particle size,zeta potential and stability of nanoparticles depend on the dosage of the κ-carrageenan.Further optimization experiment found that the κ-carrageenan dosage of 5.0 mg and 10.0 mg,Κc-ZNPs size smaller(250.1±0.9 nm and 287.6±1.4 nm),and low polydispersity index(PDI≤0.20).The study also found that there was no obvious flocculation and precipitation in the change of temperature,salt ion concentration,pH and storage time.The experiment further researches the Κc-ZNPs load performance of curcumin,and drug release of nanoparticles in simulated body fluid.Results show that the nanometer carrier has good load curcumin efficiency,and drug-loading nanoparticles(Cur/Κc-ZNPs)can reduce the release of curcumin(<40%)in simulated gastric juice(SGF,pH 2.0),and can fully release of curcumin in simulated intestinal juice(SIF,pH 7.4).In addition,the cell experiments showed that Κc-ZNPs carrier was non-toxic,and can enhance tumor cells absorb,after carrying the curcumin can effectively cause cytotoxicity,when the concentration of curcumin was 30.0 μg/mL,the survival rate of less than 10% of tumor cells. |
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