Preparation And Research Of Drug Carrier Based On Gold Nanocages

Recently, metal nanoparticles have got great attention due to their outstanding properties in optics and electromagnetism. Gold nanocages (AuNCs), a kind of hollow plasmonic nanostructures, have attracted great interests in theranostic applications and has been employed as contrast agents in optical coherence tomography, photoacoustic imaging and photothermal therapy, owing to their highly tunable localized surface plasmon resonance (LSPR) in the near-infrared (NIR) and large scattering and absorption cross sections. On the other hand, responsive hydrogel nanoparticles (or nanogels) are useful in a wide range of applications on account of their stimuli-sensitive phase transition behavior that enables drug package, delivery and release. At present, nanocomposites combined with metal nanoparticles and smart hydrogel have attracted much attention which are used as drug carriers.This thesis mainly focuses on the fabrication of core-shell AuNC/nanogel nanoparticles and their applications in drug delivery and release under different circumstances. First, ethylene glycol reduction of CF3COOAg was used to synthesis silver nanocubes with a size of 40-70 nm. Au nanocages were prepared using a remarkably simple galvanic replacement reaction and characterized by comparing LSPR peak and electron microscopy images, on that basis scale-up synthesis was achieved. Second, a pH, temperature and laser tri-responsive copolymer gel shell of poly(N-isopropylacrylamide-co-Methacrylic acid) (PNIPAm-MAA) was covered onto the AuNCs by the medium of styrene and divinylbenzene by in-situ growth method. When used as drug carriers, the core-shell nanoparticles as drug can release drugs with a response to laser light in addition to the dual response to pH and temperature caused by the gel layer itself. More importantly, thanks to its unique structure of the metal/gel, the release process of this drug carrier can be characterized with multiple optical signals such as SPR, fluorescence and SERS. The advanced spatial structure and surface characteristics of this nanostructure showed its great prospects in nano-drug delivery, photodynamic therapy, biomedical imaging, and label-free detection in biological environments.