The Preparation Of NGR-modified Graphene Oxide Nanosheets And Targeting Anti-tumor Research

Based on excellent performance with good biocompatibility,low cytotoxicity,high drug loading capacity,Graphene oxide(GO)has been extensively studied in many aspects,such as drug,genes and protein carriers.The modification of GO with peptides with the ability of active tumor-targeting has become one of the research hotspots.Combretastatin A4(CA4),the antitumor drug,can destroy tumor vascular system.CA4 can accumulate on the surface of GO by ?-? stacking and physical absorption interaction.In this paper,we mainly studies targeting cytokine NGR peptides(Asparaginate-Glycine-Arginine)covalent modify the GO,form a nanocomposite materials,and further study the biocompatibility and targeting anti-tumor effects.The main contents are as follows:(1)Studied on the prescription of CA4 and established the CA4 analysis methodology.The chromatographic conditions were determined as follows:chromatography column:Phenomenex-Gemini C18 column(4.60 × 250 mm,5 ?m);Mobile phase:methanol and water(68:32,V/V);Flow rate:0.8 mL/min;Column temperature:30 ?;Detection wavelength of 295 nm;Sample quantity:20 ?L.The methodology results showed the chromatographic method was of high accuracy and good specificity.The shake flask method was determined CA4 solubility in different solvents,the results showed that CA4 is insoluble in water and chloroform,but has good solubility in polar organic solvents.Oil-water partition coefficient determination results showed that the LogP of CA4 in different pH solution were between 2.5 and 2.7,indicated the lipotropy of CA4 is strong,and easy absorption and transport in the body.(2)Polyethyleneimine(PEI)was modified GO to prepare water-soluble amination graphene oxide(GP),cyclic NGR(CNGRCK,cNGR)peptide chemically bonded to the surface of the GP(GP-cNGR)to become active targeting carrier.In order to reduce the cytotoxicity,polyvinylpyrrolidone(PVP)was physical adsorption to the GP-cNGR to form GP-cNGR/PVP nanocarrier.The preparation GP-cNGR/PVP nanomaterials,with a hydrate particle size of 180.2 ± 3.4 nm,polydispersity index(PDI)of 0.252 ± 0.021,zeta potential of-31.6 ± 1.8 mV,had a good dispersion stability in buffer.(3)Studied the CA4-loading capacity and in vitro release behavior of drug carriers GP-cNGR/PVP.The GP-cNGR/PVP nanosystem had a CA4-loading rate of 56.3 ± 1.32%.The in vitro drug release experiments showed that the free CA4 was nearly complete released within 6 h.Instead,the drug release profile of drug delivery system was continuous and slow,the accumulative release rate within 24 h were 53.7 ± 1.59%and 51.9 ± 1.93%(n=3),respectively.(4)Cell experiments showed that GP-cNGR/PVP was no obvious toxicity,human fibrosarcoma cells(HT-1080)and breast cancer cells(MCF-7)survival rates were higher than 85%under the concentration of 2.5?40 mg/mL.GP-cNGR/PVP/CA4 had toxicity effect on both HT-1080 cells(CD13 high-level expression)and MCF-7 cells(CD13 low-level expression).But the nanosystem was more sensitive for HT-1080 cells than MCF-7 cells.Fluorescence experiments showed that GP-cNGR/PVP can significantly targeted HT-1080 cells,which exhibited a great fluorescence intensity,on the contrary,the fluorescence intensity of MCF-7 cells was very weak.The reaults of apoptosis experiments also showed that GP-cNGR/PVP/CA4 had the largest cell inhibitory effect to the target cells.In this paper,we firstly use cNGR peptide covalently bonds to the surface of GO,and preparation of a new type of nano drug carrier material,it has good bioconmpatibility and low cytotoxicity,can release drug in a sustained manner.Cells experimental results show that the GP-cNGR/PVP nano carrier has a good targeting antitumor effect.Therefore,GP-cNGR/PVP nanomaterial could be a promising targeting drug delivery carrier.