Cuiling Ren

In vitro study on the interaction between thiophanate methyl and human serum albumin.

Thiophanate methyl (MT) is one of the widely used fungicides to control important fungal diseases of crops, which has led to potential toxicological risk to public health. Several different transport proteins exist in blood plasma, but albumin only is bound by a wide diversity of xenobiotics reversibly with high affinity. We studied the interaction of MT with human serum albumin by using spectroscopic methods including fluorescence quenching technology, UV and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. The result of fluorescence titration revealed that MT could quench the intrinsic fluorescence of HSA. The binding process was exothermic and spontaneous, as indicated by the thermodynamic analyses. In addition, the studies of FT-IR spectroscopy showed that the binding of MT to HSA changed molecular conformation of HSA. The results obtained from molecular modeling showed that the interaction between MT and HSA was dominated by hydrophobic force, and there was also hydrogen bond interaction between the pesticide and the residues of HSA, which was in good agreement with the result of binding mode.

Preparation and properties of a new multifunctional material composed of superparamagnetic core and rhodamine B doped silica shell

This paper reports on the preparation of a new multifunctional nanocomposite that consists of superparamagnetic core and rhodamine B (Rh B) doped silica shell. The final products were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibration sample magnetometer (VSM), photoluminescence (PL) spectra and Fourier transform infrared spectra (FT-IR). The resultant multifunctional nanoparticles were superparamagnetic with a saturation magnetization of about 10xa0emuxa0g−1, their sizes were smaller than 150xa0nm and they possessed an emission peak at 568xa0nm with an excitation wavelength of 520xa0nm. This new material holds considerable promise in magneto-optical materials and biological applications.

Synthesis of Organic Dye-Impregnated Silica Shell-Coated Iron Oxide Nanoparticles by a New Method

A new method for preparing magnetic iron oxide nanoparticles coated by organic dye-doped silica shell was developed in this article. Iron oxide nanoparticles were first coated with dye-impregnated silica shell by the hydrolysis of hexadecyltrimethoxysilane (HTMOS) which produced a hydrophobic core for the entrapment of organic dye molecules. Then, the particles were coated with a hydrophilic shell by the hydrolysis of tetraethylorthosilicate (TEOS), which enabled water dispersal of the resulting nanoparticles. The final product was characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy, and vibration sample magnetometer. All the characterization results proved the final samples possessed magnetic and fluorescent properties simultaneously. And this new multifunctional nanomaterial possessed high photostability and minimal dye leakage.

Bi-Functional Silica Nanoparticles Doped with Iron Oxide and CdTe Prepared by a Facile Method

Cadmium telluride (CdTe) and iron oxide nanoparticles doped silica nanospheres were prepared by a multistep method. Iron oxide nanoparticles were first coated with silica and then modified with amino group. Thereafter, CdTe nanoparticles were assembled on the particle surfaces by their strong interaction with amino group. Finally, an outer silica shell was deposited. The final products were characterized by X-ray powder diffraction, transmission electron microscopy, vibration sample magnetometer, photoluminescence spectra, Fourier transform infrared spectra (FT-IR), and fluorescent microscopy. The characterization results showed that the final nanomaterial possessed a saturation magnetization of about 5.8 emu g−1and an emission peak at 588 nm when the excitation wavelength fixed at 380 nm.

L-cysteine capped CdSe as sensitive sensor for detection of trace lead ion in aqueous solution

Abstract In this study, luminescent CdSe quantum dots (QDs) were modified with L-cysteine and used as a sensitive sensor for the detection of lead ion. The fluorescence of the water soluble QDs can be quenched only by Pb2+ in Kolthoff buffer solution. The optimum experimental conditions were as follows: pH=8·0, 8·0 × 10−4M L-cysteine, reaction time=3 min and reaction temperature=293 K. The fluorescence intensity of CdSe QDs was linearly proportional to lead ion concentration from 0 to 1·00 × 10−6M with a limit of detection of 8·39 × 10−8M. The fluorescence quenching mechanism was considered to be both dynamic and static quenching acting together as quenching model. The proposed method has been successfully applied to detect the content of Pb2+ in green tea, and the recoveries were found to be 102·9–108·3% with standard addition method.

Synthesis of starch capped CdTe nanoparticles by 'green' method

Abstract CdTe nanocrystals have been successfully synthesised by a simple and green route using starch as a capping agent at room temperature. The prepared CdTe nanoparticles were characterised by XRD, TEM, UV-vis absorption and photoluminescence (PL) spectra. The XRD pattern and TEM images confirmed the formation of cubic structural CdTe nanocrystals (4–9 nm). The capped CdTe nanocrystals showed absorption peaks located within the visible range of 450–550 nm. The PL spectra indicated that their excitation and emission wavelength were located at 350 and 575 nm, respectively.

Facile way to prepare well dispersed biocompatible γ-Fe2O3 nanoparticles and their properties control

Abstract Well dispersed biocompatible γ-Fe2O3 nanoparticles with a diameter of ∼9 nm were prepared by co-precipitation in the presence of citric acid at room temperature. Particles were characterised by means of various experimental methods. Powder X-ray diffraction and selected area electron diffraction demonstrated that all products have inverse spinel structure. Vibration sample magnetometery was used to measure their magnetic property. It indicated that all products have superparamagnetic property though their saturation magnetisation varied by changing the pH and the citric acid concentration. Citrate ions coating was confirmed by Fourier transform infrared spectra, and it revealed the coating amount was related to the pH and the citric acid concentration. The morphology, size and dispersion were observed by transmission electron microscope.