Study On The Toxicity,Functionalization Of Single Walled Carbon Nanotubes And Their Applications As Nano Vectors For Drug Delivery

The viral diseases for fish at the fingerling stage was a serious fish disease which had the wide endemic areas,long duration for onset,high incidence rate,and caused great harm to fish.Conventional control measures against the viral diseases including the injection of inactivated vaccines and antiviral drugs added to the feed.However,the complexity of the operation for the injection of inactivated vaccine technology,heavy workload,and the high economic cost,thus the injection is usually used only for some fish which had high economic value.Topical or oral administration is often has the problem with drug dissolution and absorption.Especially by the biological barriers for the fish tissues and cells,the drugs were impeding access to the body and the blood transport to various tissues and cells.As a result,the drug concentrations can not reach the desired dose,and led to the limitations of the effects of drug treatment.Therefore,the selection of an effective drug carrier is the solution to the problem of drugs pass through biological barriers,the key to the treatment of viral diseases.Carbon nanotube as a novel drug carrier,which has lots of advantages include superior transmembrane,high surface energy,large drug loading,chemically stable,easily modified to achieve multi-functional,controllable and can achieve responsive sustained release,in vivo circulation time is long,and can achieve drugefficient transit and in vivo use.However,the carbon nanotubes used in the field of medicine,a major bottleneck is almost insoluble in water or organic solvents,and the safe use of carbon nanotubes there are still some disputes.Therefore,the toxicity study of carbon nanotubes on fish embryos,and by the method of modification and functionalization in order to improve its biocompatibility,enhance its solubility,and reduce toxicity to expand the application range of its applications in the biomedical fieldpremise are important.On this basis,further design and preparation of new carbon nanotube drug carrier system,and observation in the embryonic level during embryonic development in the absorption,distribution and metabolism has important scientific significance and medical applications.Based on the above points,the present work on the the toxicity of single-walled carbon nanotubes,functionalization,and preliminary research work as a drug carrier.The results obtained in this work were as follows:1.Using the soaking method,the toxicity of two single-walled carbon nanotubes for the Gobiocypris rarus embryos at 72 h.Experimental results show that:two sizes of single-walled carbon nanotubes are nontoxic for G.rarus embryos.Even at the highest concentration of 320 mg/L,while single-walled carbon nanotubes has been completely covered the surface of the embryonic membrane,however,there has no significantly affect on the development of the embryos,and embryos can hatch at the same time compared with control group.2.Using trypsin enzymatic to remove the egg membrane of G.rarus embryos to make a further study on the 72 h toxicity of two single-walled carbon nanotubes for G rarus embryos.The experimental results show that:1 mg/L trypsin at 25℃ for 5 min can effectively remove the membrane of the egg and to ensure the normal development of the embryo.Long and short single-walled carbon nanotubes have less toxicity on the G.rarus embryos,the LC50 at 72 h for long and short single-walled carbon nanotubes were:22.74(19.56-26.60)mg/L and 15.27(12.02-19.54)mg/L,respectively.3.Make the single-walled carbon nanotubes and ribavirin as the experimental materials,with the use of chemical modification,the modification of ribavirin were connected to the single-walled carbon nanotubes and synthetic products were fluorescently labeled.The synthetic products after enzymatic hydrolysis and combined with high performance liquid chromatograph analysis showed that:with the method of chemical modification,we made the single-walled carbon nanotubes as a carrier,successfully synthesized SWCNTs-BSARibavirin-FITC.Structure analysis show that the ribavirin drug loading can be achieved 7.45±0.3 1%for long single-walled carbon nanotubes and 8.21 ± 0.45%for short single-walled carbon nanotubes,the single-walled carbon nanotubes share content about 76%.4.Using laser confocal microscopy and quantitative PCR,we detected the absorption,distribution,and initial metabolism of SWCNTs-BSA-Ribavirin-FITC in G rarus embryos.The experimental results show that:both long and short single-walled carbon nanotube complex had the same effects.The complexs can enter the embryos between the 48 h and 60 h,and enriched in G.rarus head,eyes and vascular system,but can not enter the yolk sac.72 h recovery experiments show that,the complex fluorescent spots in the body completely disappeared within 72 h,and the related gene expression would be back to normal level.This study shows that single-walled carbon nanotubes are nontoxic to G.rarus embryos,and can be used as ideal drug carrier for the prevention and treatment of fish diseases.