Preparation Of Gold Nanorods And Their Experimental Study In CT Imaging

Objective1.To synthesize gold nanorods(GNRs) by seed-mediated growth method and GNRs could be controlled ratio of lenth to width by changing experimental parameters. GNRs could have the same size,good dispersion and possess specific opticsn absor-ption bands.2.To evaluate imaging effects of GNRs by CT scanning images and value of hounsfild unit,and to analyze effects of GNRs’ concentration on CT imagings and lay the foundation for the next experiment.Methods1.Gold seeds were first synthesized,CTAB solution was added to the HAuC14solution and mixed liquids were gentle stirring,and then the cold NaBH4solution was addend to the mixture rapidly and mixture was continued to stir for2minutes.Second,growth solution was prepared,the CTAB solution was added to the mixture of HAuC14and AgNO3,and mixture solution was stirred gently,and ascorbic acid was added to the mixture solution.Finally,the seeds were added to the growth solution,and gold seeds growed in to GNRs.All of the final solution will be centrifuged15minutes and the surfactant was removed,the gold nanorods were collected,and then were resuspended in deionized water,and the process was repeated for further purification.UV figure of GNRs was detected by the UV fluorescence spectrometer;Size and aspect observed by electron microscope images.The GNRs’ ratio and their average were statistical analysis on TEM images.2.GNRs solution were prepared before CT scanning:taking the same volume fo solutions with different concentrations place into containers of the same size.These containers were placed in the CT scan bed,the scanning voltage and current are120Kv,200mA,respectively,the thickness was0.625mm,the values of Hounsfild Unit were measured on CT scanning images by selecting the same size at the same thickness,and then statistical analysis was completed.Resules1.The structure,dispersion and size were observed by TEM images. The ratio of lenth to width of GNRs were①2.2±0.2②2.8±0.3③3.6±0.3,respectively.UV pictures showed that the GNRs possessed two absorption bands.One was longitudinal surface plasmon resonance,another was transverse surface plasmon resonance,and with the increase of ratio of lenth to width,the longitudinal Plasmon band located from visible region to the near infrared(NIR) region.2.CT images showed that visual difference of the different concentration of GNRs was small.The value of Hounsfild Unit and scatter dot diagram showed that CT value increased with the increase of concentration of GNRs.Conclusion1.GNRs were successful synthesized by seed-mediated growth method,and were controlled ratio of lenth to width by changing experimental parameters.GNRs are characterized by transmission electron microscopy(TEM) and UV-vis spectrometer. GNRs have the same size，good dispersion and possess two absorption bands,and with the increase of ratio of lenth to width,the longitudinal Plasmon band located from visible region to the near infrared(NIR) region.2.Results showed that CT value increased with the increase of concentration of GNRs and the result layed the foundation for the next experiment.