Gold Nanorods Based Plasmonic Probe For Drug Delivery And Bio-imaging Studies

In the past ten years, technology has achieved a great advance in biology. People begin tointroduce nanomaterials into the drug carrier and hope the nano-drug carriers can have a good effecton the treatment of disease. But the facts are not always true as people think. We do not know howthe nanomaterials act when they enter the cells or people’s body and the situation makes it becomea problem for researchers to apply them into practice. Therefore, investigating the release kineticsof the nano-drug carriers when they enter the cell are of great significance for us. Combining theunique plasmon resonance properties of metal nanoparticles and biocompatibility of mesporoussilica or amphiphilic block copolymers, the nanocomposites demonstrate great potentials in cancertherapy. Based on this background, we synthesized two different near-infrared plasmon core-shellprobes—mesporous silica coated and amphiphilic block copolymers coated gold nanorods, and alsohad investigations of their applications in the studying the release kinetics of nano-drug carriers andphotoacoustic imaging.(1) Mesporous silica coated gold nanorods were designed and synthesized. Gold nanorods wereobtained by the seed-mediated method. By adjusting the amount of AgNO3, the diluted times ofseeds, temperature and other related factors, we achieved a series of gold nanorods with differentshapes and aspect ratios. The gold nanorods with large aspect ratio can be oxidized to short ones byH2O2. The short gold nanorods then are coated with mesporous silica. The spectroscopic andmorphology properties of these nanoparticles were characterized by UV-fluorescence spectra,transmission electron microscopy (TEM), scanning electron microscopy (SEM).(2) Near-infrared plasmon core-shell probe were achieved by immobilizing the mesporous silicacoated gold nanorods on the ITO. This probe monitored the adsorption and desorption process ofdifferent concentrations of doxorubicin(DOX) in the mesporous silica coated gold nanorods. Weused dark field microscopy(DFM) to monitor the whole adsorption and desorption process ofDOX.(3) We synthesized the amphiphilic block copolymers---Polystrene-b-Poly(acrylic acid)(PSPAA) coated gold nanorods by self-assembly. This near-infrared plasmon core-shell probes areejected into mice to be used for photoacoustic imaging. The spectroscopic and morphologyproperties of these nanoparticles were characterized by UV-fluorescence spectra, transmission electron microscopy (TEM). And the photoacoustic imaging images were obtained by thephotoacoustic imaging system.