Jinmiao Zhu

Tunable surface plasmon resonance of Au@Ag2S core–shell nanostructures containing voids

A novel rodlike core–shell nanostructure containing voids between shell and core has been effectively synthesized by the Kirkendall effect. The Au@Ag2S nanoparticles exhibit preferable optical properties due to integrating the absorption behaviors of the Au cores and the Ag2S shells and existence of voids. When Ag is coated on the surface of Au nanorods, the SPR absorption of the Au nanorods shows a blue shift. While Ag is transformed to Ag2S, the SPR absorption of the Au nanorods shifts to high wavenumber. Different shells could adjust and control the SPR absorption of Au nanorods. Moreover, the voids endow the nanostructured materials with other new functions such as catalysis, drug delivery and so on.

Synthesis of hollow magnetic and luminescent bifunctional composite nanoparticles

Composite nanoparticles consisted of Au-coating Co superparamagnetic cores and CdSe shells have been synthesized. In-situ reduction and cation exchange methods have been applied in the synthetic process. The composite nanoparticles have been characterized by various methods. Experimental results showed that the oxidation of cobalt nanoparticles might be restrained by a gold shell. The as-prepared nanoconjugates exhibited magnetic and luminescent properties. The bifunctional nanoparticles can be used as detecting agent to analyze tumor cell in vitro and in vivo. We believe that the results could be used as a reference by researchers engaged in both fundamental and applied biomedicine.

Biomimetic synthesis of the arachidic acid/Ag x Cd y S nanocomposite films

AgxCdyS nanoparticles were obtained in arachidic acid (AA) monolayer containing Ag+ and Cd2+ under H2S flow. The AA/AgxCdyS monolayers were deposited onto solid substrate to prepare LB films. The UV-vis spectrum showed that the LB film exhibited notable quantum-size effect. The small-angle X-ray diffraction revealed periodic structure of the LB films. The molar ratio of Ag to Cd in AA/AgxCdyS film was ca. 1 : 5 as measured by the XPS. TEM and FTIR spectroscopy showed that the head-groups of arachidic acid molecules controlled formation of AgxCdyS nanoparticles in the monolayer.

Effects of Calcium Ions on Thermodynamic Properties of Mixed Bilirubin/Cholesterol Monolayers

The mixed monolayer behavior of bilirubin/cholesterol was studied through surface pressure-area (π-A) isotherms on aqueous solutions containing various concentrations of calcium ions. Based on the data of π-A isotherms, the mean area per molecule, collapse pressure, surface compressibility modulus, excess molecular areas, free energy of mixing, and excess free energy of mixing of the monolayers on different subphases were calculated. The results show an expansion in the structure of the mixed monolayer with Ca2+ in subphase, and non-ideal mixing of the components at the air/water interface is observed with positive deviation from the additivity rule in the excess molecular areas. The miscibility between the components is weakened with the increase of concentration of Ca2+ in subphase. The facts indicate the presence of coordination between Ca2+ and the two components. The mixed monolayer, in which the molar ratio of bilirubin to cholesterol is 3:2, is more stable from a thermodynamic point of view on pure water. But the stable 3:2 stoichiometry complex is destroyed with the increase of the concentration of Ca2+ in subphase. Otherwise, the mixed monolayers have more thermodynamic stability at lower surface pressure on Ca2+ subphase.

A study of the fractal structure of the precipitate and the mechanism of its formation from the gallbladder bile of a patient

The precipitation of three kinds of structures from gallbladder bile of a patient, fractal structure, regular crystal structure, and small disperse granules, was observed in the same sample using Field Emission Gun-Scanning Electron Microscopy (FEG-SEM). The results indicated that there was a transition from a linear equilibrium system to a nonlinear and nonequilibrium system, which was discussed using the theory of entropy. The chemical compositions of these three different kinds of precipitates were determined by energy dispersive X-ray spectroscopy (EDS). This experimental result revealed that Na and Cl played important roles in the formation of the fractal and crystal structures. Besides, the Aggregation-Diffusion-Fractal (ADF) model was used to explain the growth mechanism of the fractal.

The effect of the initial reactant molar ratio and doping with Fe3+ on the formation of calcium bilirubinate in water-oil microemulsions

A series of calcium bilirubinate nanoparticles were synthesized in microemulsions consisting of polyoxyethylene octylphenol ether (Triton X-100), n-hexyl alcohol (n-C6H13OH), cyclohexane (c-C6H12), and an aqueous solution. The particles were characterized by Fourier transform infrared (FT-IR) spectra, powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), transmission electron microscopy (TEM), and zeta potential measurements. The results showed that the initial CaCl2/Na2BR molar ratio and the molar ratio of water to surfactant (ω0) influenced the morphology and microstructure of calcium bilirubinate nanoparticles and the sites of Ca2+ coordination to BR2−. The composition of synthesized calcium bilirubinate was nonstoichiometric. The stability of calcium bilirubinate nanoparticles dispersed in water changes as the Ca2+/BR2− molar ratio and solution pH varied. Dopant Fe2+ ions played a certain role in the simulated mineralization of calcium bilirubinate. A possible mechanism of calcium bilirubinate formation in inverse microemulsions is discussed.