| Over the past few decades,cancer has been one of the most fatal diseases threatens to human.Chemotherapy is a routine method for cancer treatment due to the prominent clinical efficiency in current therapeutic approaches.However,most of the chemotherapeutic drugs have limits including poor water solubility,short blood half-lives,multi-drug resistance and serious side effects.In order to overcome these barriers,the researchers have designed a variety of therapeutic strategies.In recent years,targeted treatment of tumor based on nano-carriers has received extensive attention.As a drug carrier for cancer chemotherapy,it can significantly improve the water solubility of chemotherapeutic agents,prolong its half-lives in vivo and reduce its systemic toxicity.Based on the high drug loading and high biocompatibility of cyclodextrin,this projectattempts to develop a nano-drug system by using folic acid as a targeting molecule and a cyclodextrin as the main skeleton.Using?-cyclodextrin as initiator to induce ring-opening polymerization of?-caprolactone,a new?-cyclodextrin copolymer?-CD-CL with good biocompatibility and biodegradability was constructed.Furthermore,folic acid-targeted?-cyclodextrin copolymer(?-CD-CL-FA)was prepared by coupling with folic acid.Folic acid targeting?-cyclodextrin loaded curcumin nanoparticles(FA-Cur-NPs)were prepared by solvent volatilization using curcumin as model drug.By binding specifically to folic acid receptor overexpressed in cancer cells,curcumin was delivered to cancer cells by receptor-mediated endocytosis,which significantly increases the concentration of curcumin in cancer cells and treat the cancer cells.The main content and conclusions were summarized as follow:Firstly,?-cyclodextrin copolymer?-CD-CL was synthesized by ring-opening polymerization of?-cyclodextrin and?-caprolactone under the catalysis of stannous octoate.Then folic acid-targeted?-cyclodextrin copolymer?-CD-CL-FA was prepared by coupling with folic acid.The structure of the obtained polymers was determined by FT-IR,~1H-NMR and GPC.Secondly,folic acid-targeted curcumin loaded?-cyclodextrin nanoparticles(FA-Cur-NPs)were prepared by solvent volatilization using?-CD-CL-FA as carrier.The physicochemical properties of FA-Cur-NPs including particle size,polydisperse index(PDI),zeta potential,apparent morphology and stability in vitro were evaluated,and the drug release behavior of FA-Cur-NPs in vitro was also investigated.The optimal conditions were obtained by single factor investigation.The drug loading of FA-Cur-NPs was(20.27±1.36)%and the encapsulation efficiency was(95.64±0.92)%.FT-IR analysis concluded that curcumin was successfully embedded in the nanoparticles and the particle size of FA-Cur-NPs(151.8±1.28)nm,PDI(0.073±0.024),and Zeta potential(-15.8±1.05)mV were measured by dynamic light scattering grainometer.TEM observed that the FA-Cur-NPs were approximately spherical,and the particle size was consistent with the results obtained by the Malvern Zetasizer.The stability study showed that the diameter of FA-Cur-NPs had no obvious change within 72 hours and polydispersity coefficient was less than 0.2.In vitro release studies showed that FA-Cur NPs had sustained release properties,and curcumin release was more in slightly acidic environment while lower in normal tissues,which was helpful to reduce the damage of drugs to normal tissues.Thirdly,the safety and in vitro efficacy of FA-Cur-NPs were evaluated by MTT test.Cytotoxicity test showed that the carrier materials(?-CD-CL-FA and?-CD-CL)had good biocompatibility.Besides,Pharmacodynamic test in vitro showed that the cytotoxicity of FA-Cur-NPs on HeLa cells was significantly stronger than that of Cur-NPs when the concentration of curcumin was 2.5~40?g/mL.After adding free folic acid,the cytotoxicity of FA-Cur-NPs was significantly weakened,which proved that FA-Cur-NPs were mainly mediated active targeting by folic acid.Furthermore,cell uptake study showed that FA-Cur-NPs had more drugs into the cells through folate receptor mediated endocytosis pathway than that of Cur-NPs and(FA-Cur-NPs+free FA)when the concentration of curcumin was 30?g/mL and cell uptake time was about 3 h,which was further demonstrated that FA-Cur-NPs undergo cellular uptake by folate receptor-mediated endocytosis.Lastly,in vivo imaging system was used to observe curcumin distribution of FA-Cur-NPs in the tumor tissues and organs of BALB/c-nu nude mice injected with Cur-DMSO?Cur-NPs?FA-Cur-NPs at 3 and 7 h by establishing HeLa cervical carcinoma model.The results showed that curcumin was in mass distribution and mainly accumulated in liver and kidney in Cur-DMSO and Cur-NPs group,while mainly concentrated in tumor site in FA-Cur-NPs group.The inhibitory effects of various drug groups on solid tumor of HeLa cervical cancer in nude mice were studied by continuous administration for thirty days.The results showed that FA-Cur-NPs had the most significant inhibitory effect on HeLa cervical carcinoma solid tumor compared with Cur-DMSO and Cur-NPs.Furthermore,H&E stained sections of organs and tumor tissue was investigated and found that the area of tissue necrosis in FA-Cur-NPs group was larger than that in Cur-DMSO and Cur-NPs group.There were no obvious pathological changes in the liver and kidney of FA-Cur-NPs group while Lymphocyte infiltration was found in the liver and kidney cells of Cur-DMSO and Cur-NPs.The results showed that FA-Cur-NPs group had better tumor targeting ability compared with Cur-DMSO and Cur-NPs group,curcumin was encapsulated by the carriers?-CD-CL-FA can reduce systemic toxicity effectively.In summary,a novel nano-drug delivery system based on folic acid-targeted amphiphilic?-cyclodextrin copolymer was constructed.Studies have shown that the carrier has good biocompatibility,targeting ability and high drug loading capacity,leading to dramatically enhanced bioavailability of curcumin in vivo.All in all,it was promising to provide a good nano-carrier for hydrophobic drugs. |
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