Preparation And Application Of Materials Based On Au Nanoclusters

The rapid development of nanotechnology has brought a new class of fluorescent nanomaterials, fluorescent noble metal nanoclusters, into sight. The noble metal, such as Au, Ag, Cu and Pt, nanoclusters are usually composed of a few to several hundred atoms. The size of the clusters is smaller than 2 nm, which is close to the Fermi wavelength. Due to their special electronic structure, metal nanoclusters show a range of molecular-like properties, including unique optical, chemical, electrical, and catalytic properties, which give rise to a wide range of application of them. Among these noble metal nanoclusters, the Au nanoclusters ?AuNCs? have attracted much attention because of the convenient synthesis, long fluorescent life, small size, good fluorescence intensity, excellent optical/colloidal stability and biocompatibility.By a novel, simple and reproduceable method, uniform and well dispersed Fe₃O₄@PAA/AuNCs/ZIF-8 composite nanoparticles were prepared. As has been reported, AuNCs can be used for fluorescence imaging and computed tomography ?CT? imaging, meanwhile, Fe₃O₄ is agent for magnetic resonance imaging ?MRI?. Therefore, the prepared Fe₃O₄@PAA/AuNCs/ZIF-8 nanoparticles integrate three modes of imaging ?fluorescence imaging, CT imaging and MRI? into a single system. Moreover, the composite nanoparticles possess ultrahigh anticancer drug loading capacity and dual pH-responsive drug release property. In addition, in vitro and in vivo toxicity tests testify a good biocompatibility of the Fe₃O₄@PAA/AuNCs/ZIF-8 nanoparticles. All the results show that the prepared Fe₃O₄@PAA/AuNCs/ZIF-8 composite nanoparticles as drug carrier and multimodal bio-imaging agent have potential for three modal cancer imaging and tumor growth inhibition simultaneously.Except for bio-imaging, fluorescent AuNCs can also be used for heavy metal ions detection. In the following work, a portable, sensitive and recyclable fluorescent test paper was prepared to detect heavy metal ions Hg²⁺ and Pb²⁺ selectively based on the aggregation-induced fluorescence quenching ?AIFQ? and aggregation-induced fluorescence enhancement ?AIFE? properties of AuNCs. It is worth noting that the used test papers can recover to original fluorescent state after immersed into ethylenediamine tetraacetic acid ?EDTA? saturated solution and the recovered test papers can be used for additional rounds of ions detection. All the results show that the prepared fluorescent test papers can act as a fluorescent sensor for circulating detection of heavy metal ions Hg²⁺ and Pb²⁺ by naked eyes.