The Study On The Optical Properties And Tumor Imaging Of NIR-Emitting Gold Nanoaparticles

Luminescent gold nanoparticles(AuNPs)possessed unique properties such as ultrasmall size,large Stoke shift,the feasibility of surface modification and great biocompatibility,thus these advantages made them become highly attractive to research field such as sensor,biological imaging and disease diagnosis.However,most of the luminescent probes are designed based on the single emission intensity change,which might be susceptible to the light source,environment conditions and the concentration of probe.The result analysed according to the change of single emission intensity may be erroneous.In the field of bioimaging application of luminescent AuNPs,the analysis results are depended on not only the fluorescence intensity changes,but also the tumor targeting efficeincy of luminescent AuNPs.At present the most reported luminescent AuNPs had poor tumor targeting efficeincy,it's urgent to improve tumor targeting efficiency without any increase in biotoxicity.In this dissertation,regulating luminescent AuNPs with dual emissive properties and improving the tumor targeting efficiency of luminescent AuNPs were investigated in detail,the main research contents and results are as follows:A facile strategy was reported for the transformation of single NIR-emitting AuNPs to dual-NIR-emitting bimetallic Ag@AuNPs based on the robust reactivity toward Ag(I)ions.The reactivities toward Ag(I)ions were found to be significantly different between visibleand NIR-emitting glutathione(GSH)coated AuNPs: the high GSH surface coverage on the 610 nm-emitting AuNPs resulted in a reversible interaction due to enough surface steric hindrance to resist Ag(I)ions from interaction with the Au(0)core,whereas the low GSH surface coverage on the 810 nm-emitting AuNPs led to both antigalvanic reaction and Ag(I)-carboxylate shell formation on the surface of the AuNPs,which were responsible for the formation of a new emissive center at 705 nm.This strategy was also demonstrated to exhibit excellent generalization toward various NIR-emitting AuNPs with surface chemistries containing carboxyl groups,opening a new pathway of tailoring the optical properties of metallic NPs through surface reactivity.The detailed results are given in the second chapter of this dissertation.The thio-glucose modified gold nanoparticles(TG-AuNPs)were successfully synthesized,and TG-AuNPs were applied to realize the high tunor targrting effciency.Ultrasmall-sized(~2.5 nm)NIR-emitting TG-AuNPs were synthesized by adjusting the reaction condition such as such as the ratio between thiolglucose and chloroauric acid trihydrate,pH,temperature and time,etc.The cell cytotoxicity,cell uptake,pharmacokinetic and biodistribution experiment of TG-AuNPs were carried out,the investigation results showed that the NIR-emitting TG-AuNPs could not only be passively targeted in the tumor,but the special surface chemical properties of TG-AuNPs effectively made the targeting efficeincy increased.This investigation which improved the tumor targeting efficiency of luminescent AuNPs would provide a new pathway.The detailed results are given in the third chapter of this dissertation.