Preparation Of Gold Nanparticles Preparation Of Functional Gold Nanomaterials And Application Of Intracellular Active Substances By Imaging Detection And Targeted Grug Delivery

In recent years,due to the intense plasmon absorption bands in the visible wavelength regime,the focus on the applications of Au nanoparticles are much more.Noble metal nanoclusters,especially gold nanoclusters?AuNCs?that protected by bovine serum albumin?BSA?,can exhibit molecule-like electronic transition between HOMO-LUMO energy due to their small size.AuNRs exhibit two different plasmonic modes including transverse and longitudinal modes.The gold nanoparticles have attracted much attention recently and have widely used in biosensing,biolabeling,optical imaging,and so on.1.Gold nanoclusters?AuNCs?protected by bovine serum albumin?BSA?are known to emit red fluorescence?peaking at 650 nm?on photoexcitation with ultraviolet light?365 nm?.On addition of Cu²⁺ions,fluorescence is quenched because Cu²⁺complexes amino acid units in the BSA chain.fluorescence is,however,restored if pyrophosphate?PPi?is added because it will chelate Cu²⁺and remove it from the BSA coating on the AuNCs.Because PPi is involved in the function of telomerase,the BSA@AuNCs loaded with Cu²⁺can act as a fluorescent probe for determination of the activity of telomerase.A fluorescent assay was worked out for telomerase that is highly sensitive and has a wide linear range?10 nU to 10 fU per mL?.The fluorescent probe was applied to the determination of telomerase activity in cervix carcinoma cells via imaging.It is shown that tumor cells can be well distinguished from normal cells by monitoring the differences in intracellular telomerase activity.2.Drug delivery which can offer efficient and localized drug transportation together with imaging capabilities is highly demanded in the development of cancer theranostic approaches.Herein,we report the construction of bovine serum albumin?BSA?gold nanoclusters?BSA@AuNCs?for cell fluoresce imaging and target drug delivery.BSA@AuNCs were modified with cyclic arginine-glycine-aspartate?cRGD?with the product RGD-BSA@AuNCs to enhance the cell internalization of the nanoclusters.Furthermore,doxorubicin?DOX?,a widely used a chemotherapy drug,wasalsousedtomodifyRGD-BSA@AuNCs.Thefinaldesignof DOX/RGD-BSA@AuNCs system was constructed through the disulfide bond.As the disulfide bonds were cleaved by glutathione?GSH?in cancer cells,DOX-SH molecules were released from the nano-system to inhibit the growth of cancer cells.The as-prepared DOX/RGD-BSA@AuNCs system cannot only be used to deliver drug but also to achieve the antitumor effect by in vivo imaging,demonstrating its promising applications in cancer treatment.3.Integration of cancer cell imaging and therapy is critical to biomedical studies andclinicalpractice.Here,amultifunctionalgoldnanoprobe?DOX/RGD-DNA@AuNRs?is designed for simultaneous miRNA-responsive fluorescence imaging and therapeutic monitoring of cancer.Gold nanorods assembled with RGD as the targeted moiety and a carboxy fluorescein?FAM?as the recognition element and signal switch.DOX were physically intercalated into a DNA assembly immobilized on gold nanorods?AuNRs?.DOX/RGD-DNA@AuNRs is RGD receptor-targeted delivered into the cancer cells,and the fluorescence is lighted with the release of FAM by intracellular microRNA?miRNA?,resulting in an efficient method for cancer cell imaging and therapy.This work provides a simple but powerful protocol with great potential in cancer imaging,therapy,and therapeutic monitoring.