Preparation And Application Of Multifunctional Nanoparticles Based On Gold Nanoclusters

Nanoparticles with diameters between 1-100 nm suffer surface effect, quantum size effect, small size effect and macroscopic quantum tunneling effect, endowing nanoparticels a lot of special properties in force, magnetic, light, sound, heat and electricity compared with macroscopical object. Therefore, research of the preparation and application of nanomaterials has become a focus in the field of materials science research today. Currently, gold nanoclusters (AuNCs) have attracted a lot of attentions in the field of cancer diagnosis and treatment as a new fluorescence nanomaterial. Compared with traditional fluorescent materials such as quantum dots and organic dyes, AuNCs possess advantages of low toxicity, excellent chemical and optical stability, long fluorescent lifetime and high fluorescent intensity, etc. Based on the good biocompatibility and easy preparation, the AuNCs as new fluorescent reagents used in biomedical researchs are attracting more and more attention.By overcoming disadvantages of single imaging methods and combining then-advantages, the development of multifunctional nanoprobes has become increasingly significant in cancer diagnosis and therapy. This paper presents a novel and convenient method to prepare uniform and dispersive Gd3+-aggregated AuNCs encapsulated by silica shell (Gd3+-A-AuNCs@Si02) nanoparticles, possessing fluorescence intensity that is 3.8 times of discrete AuNCs. Simultaneously, Gd3+-based complexes can be used for magnetic resonance (MR) imaging and Au-based nanoparticles can be used for computed X-ray tomography (CT) imaing. Finally, experiments show that the prepared nanoparticles have potential for multimodal (fluorescence/CT/MR) cancer imaging.In the following work, we developed a simple and universal method to obtain yolk-shell aggregated gold nanoclusters encapsulated by polyacrylic acid/mesoporous silica shell (A-AuNC@PAA/mSiO2) nanoparticles by coating bifunctional imaging nuclear into the mesoporous silica shell. We used polyacrylic acid as the template, and the mesoporous silica shell endows nanoparticles the ability of drug delivery. Experiment results prove that the nanoparticels can be used for in vivo and in vitro dual-modal imaging and drug delivery, integrating diagnosis and treatment into cancer treatment.