The in vitro and in vivo toxicity of gold nanoparticles

Gold nanoparticles,owing to their unique physicochemical and optical properties,well-established synthetic methods and easy modifications,have been widely used in biomedical science.Therefore,for their safe and efficient applications,much attention has been given to the toxicological evaluations of gold nanoparticles in biological systems.A large number of studies focusing on this problem have been carried out during the past years.However,the researches on gold nanoparticles toxicity still remain fragmentary and even contradictory with each other.This may be caused by the variety in experimental conditions.In this review,we aim to provide a better understanding about the in vitro and in vivo toxicity of gold nanoparticles by reviewing and describing the up to date literatures related to this problem and we mainly focused on these properties such as the particle size and shape,the surface charge and modification.Besides,we also summarized the adverse effect of gold nanoparticles on immune systems and analyzed the origin of the toxicity.

Inhibition of thrombin by functionalized C_(60)nanoparticles revealed via in vitro assays and in silico studies

The studies on the human toxicity of nanoparticles（NPs） are far behind the rapid development of engineered functionalized NPs. Fullerene has been widely used as drug carrier skeleton due to its reported low risk. However, different from other kinds of NPs, fullerene-based NPs（C_（60） NPs） have been found to have an anticoagulation effect, although the potential target is still unknown. In the study, both experimental and computational methods were adopted to gain mechanistic insight into the modulation of thrombin activity by nine kinds of C_（60） NPs with diverse surface chemistry properties. In vitro enzyme activity assays showed that all tested surface-modified C_（60） NPs exhibited thrombin inhibition ability. Kinetic studies coupled with competitive testing using 3 known inhibitors indicated that six of the C_（60） NPs, of greater hydrophobicity and hydrogen bond（HB） donor acidity or acceptor basicity, acted as competitive inhibitors of thrombin by directly interacting with the active site of thrombin. A simple quantitative nanostructure-activity relationship model relating the surface substituent properties to the inhibition potential was then established for the six competitive inhibitors.Molecular docking analysis revealed that the intermolecular HB interactions were important for the specific binding of C_（60） NPs to the active site canyon, while the additional stability provided by the surface groups through van der Waals interaction also play a key role in the thrombin binding affinity of the NPs. Our results suggest that thrombin is a possible target of the surface-functionalized C_（60） NPs relevant to their anticoagulation effect.

Electrosynthesis and catalytic properties of silver nano/microparticles with different morphologies

Electrosynthesis of powdery silver particles can be effectively carried out with an H20-oleic acid or an H20-glycerol mix solvent （volume ratio 1：1） as the electrolytic medium and AgN03 as the supporting electrolyte. Experimental results indicate that the presence or absence of the surfactant sodium dodecyl sulfate （SDS） and the choice of electrolytic medium have a significant impact on the shape and size of the prepared Ag particles. With H20-glycerol as the electrolytic medium, spherical Ag nanoparticles can be obtained in the presence of SDS （0.6g/L）, while an Ag sample electrodeposited without SDS has a dendritic microcrystalline structure. For the reduction of methyl orange （MO） and methylene blue （MB） with NaBH4 as the reducing agent, the spherical Ag nanoparticles exhibit much better catalytic activity than the dendritic Ag microparticles. Further investigations show that surface modification by an oleic acid medium could greatly improve the catalytic activity of the electrodeposited Ag particles for the reduction of MO and MB.

Preparation and Characterization of Poly(amide-imide)/ZnO Nanocomposites Containing Pendent Benzoxazole and Benzimidazole Segments

In the present investigation, novel poly（amid-imide）/zinc oxide nanocomposites（PAI/Zn O NCs） containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles（Zn O NPs） were successfully prepared via the ex situ method. Poly（amid-imide）（PAI） was prepared by direct polycondensation of 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole（DCA） with 5-（2-benzimidazole）-1,3-phenylenediamine（DAMI） and provided the polymeric matrix with well-designed groups. The surface of Zn O NPs was functionalized with 3-aminopropyltriethoxysilane（APS） coupling agent to have a better dispersion and enhancing possible interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the Zn O surface was determined by thermogravimetric analysis. PAI/Zn O nanocomposites were characterized by Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, and scanning electron microscopy（SEM）. SEM analysis showed that the modified Zn O nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer.