A gold tetrahedral nanocage, i.e., a tetrananocage, that converts near-infrared （NIR） light into heat was fabricated by using a simple method. Silver tetrahedra with good homogeneity and dispersity were synthesized by a hydrothermal route. Gold tetrananocages were obtained using a galvanic replacement reaction between Ag tetrahedra and HAuC14 solution. The surface plasmon resonance （SPR） of gold tetrananocages was tuned from 412 nm to 850 nm through controlling the volume of HAuC14 solution added. This Au tetrananocage can effectively convert NIR light into heat when the SPR couples with the exciting light. When cancer cells are cultured with the gold tetrananocages for several hours and irradiated, the gold tetrananocages destroy the cancer cells effectively and demonstrate themselves to be a good candidate for combating cancer.
A novel nontoxic, magnetic, and luminescent nanoprobe is prepared by using complex nanoparticles, which are composed of Fe304 nanoparticles and Mn-doped ZnS quantum dots （QDs）. The nanocomposite probe can provide visible optical and magnetic resonance images simultaneously. Compared with the previously toxic cadmium and mercury based QDs, the superiority of the Mn-doped ZnS QDs is little virulence. The structure and the properties of the particles are characterized by energy dispersive X-ray analysis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, and vibrating sample magnetometer.
The coupling of local surface plasmon （LSP） of nanoparticle and surface plasmon （SP） mode produced by metal film can lead to the enhanced electromagnetic field, which has an important application in enhancing the fluorescence of quantum dots （QDs）. Herein, the Ag nanocube and Ag film are used to enhance the fluorescence of CdSe QDs. The enhancement is found to relate to the sizes of the Ag nanocube and the thickness of the Ag film. Moreover, we also present the fluorescence enhancement caused by only SP. The result shows that the coupling between metal nanoparticles and metal film can realize larger field enhancement. Numerical simulation verifies that a nanocube can localize a strong electric field around its comer. All the results indicate that the fluorescence of QDs can be efficiently improved by optimizing the parameters of Ag film and Ag cubes.
Gold （Au） nanocage@SiO2 nanoparticles are prepared by a novel approach. The silver （Ag） nanocube@SiO2 structure is synthetized firstly. Next, the method of etching a SiO2 shell by boiling water is adopted to change the penetration rate of AuCl4- through the SiO2 shell. AuCl4- can penetrate through silica shells of different thickness values to react with the Ag nanocube core by changing the incubation time. The surface plasma resonance （SPR） peak of synthetic Au nanocage@SiO2 can be easily tuned into the near-infrared region. Besides, CdTeS quantum dots （QDs） are successfully connected to the surface of Au nanocage@SiO2, which testifies that the incubation process does not change the property of silica.
