Yan-Juan Gu

Nuclear penetration of surface functionalized gold nanoparticles.

Free gold nanoparticles easily aggregate when the environment conditions change. Here, gold nanoparticles (AuNPs) with average diameter of 3.7 nm were prepared and then modified with poly(ethylene glycol) (PEG) to improve stability. The gold nanoparticles were first surface-modified with 3-mercaptopropionic acid (MPA) to form a self-assembled monolayer and subsequently conjugated with NH(2)-PEG-NH(2) through amidation between the amine end groups on PEG and the carboxylic acid groups on the particles. The biocompatibility and intracellular fate of PEG-modified gold nanoparticles (AuNP@MPA-PEG) were then studied in human cervical cancer (HeLa) cells. Cell viability test showed that AuNP@MPA-PEG did not induce obvious cytotoxicity. Both confocal laser scanning microscopy and transmission electron microscopy demonstrated that AuNP@MPA-PEG entered into mammalian cells and the cellular uptake of AuNP@MPA-PEG was time-dependent. Inductively coupled plasma mass spectrometry and confocal microscopy imaging further demonstrated that AuNP@MPA-PEG penetrated into the nucleus of mammalian cells upon exposure for 24 h. These results suggest that surface modification can enhance the stability and improve the biocompatibility. This study also indicates that AuNP@MPA-PEG can be used as potential nuclear targeted drug delivery carrier.

Gold-doxorubicin nanoconjugates for overcoming multidrug resistance

UNLABELLED Multidrug resistance (MDR) is a major clinical obstacle to the success of cancer chemotherapy. Here we developed a gold-doxorubicin (DOX) nanoconjugates system to overcome MDR. Gold nanoparticles (AuNPs) were first PEGylated as Au-PEG-NH(2), and DOX was then grafted onto AuNPs via a cleavable disulfide linkage (Au-PEG-SS-DOX). Confocal images revealed that the extent of intracellular uptake of Au-PEG-SS-DOX was greater than that of free DOX in the MDR cells, and inductively coupled plasma mass spectroscopy analysis further confirmed that AuNPs significantly increased the level of drug accumulation in MDR cells at a nanoparticles dose greater than 15 μM. The cytotoxicity study demonstrated that the Au-PEG-SS-DOX nanoconjugates system efficiently released the anticancer drug DOX and enhanced its cytotoxicity against MDR cancer cells. This study highlights the potential of using AuNPs for overcoming of MDR in cancer chemotherapy. FROM THE CLINICAL EDITOR This study demonstrates that gold nanoparticles can be successfully applied to overcome MDR in cancer chemotherapy.

Electro-oxidation of Methanol on Pt Particles Dispersed on RuO2 Nanorods

The successful attachment of 1-3 nm Pt nanoparticles to the surface of amine-functional RuO 2 nanorods through a simple, two-step chemically controlled procedure is reported here. The nanocomposites were characterized by transmission electron microscopy (TEM) and X-ray diffraction. TEM images showed that the monodispersed Pt nanoparticles were highly stable against thermal treatment. The electro-oxidation of methanol in sulfuric acidic solution was studied on RuO 2 -supported Pt nanoparticles by cyclic voltammetry and chronoamperometry. All of the electrochemical results show that RuO 2 /Pt catalysts exhibit high activity for methanol oxidation that results from the high electroactive surface area of Pt nanoparticles and the effect of RuO 2 . These results demonstrate the feasibility of using metal oxide nanorods in certain fuel cell applications.

Nanotherapeutics in angiogenesis: synthesis and in vivo assessment of drug efficacy and biocompatibility in zebrafish embryos

Background Carbon nanotubes have shown broad potential in biomedical applications, given their unique mechanical, optical, and chemical properties. In this pilot study, carbon nanotubes have been explored as multimodal drug delivery vectors that facilitate antiangiogenic therapy in zebrafish embryos. Methods Three different agents, ie, an antiangiogenic binding site (cyclic arginine-glycin-easpartic acid), an antiangiogenic drug (thalidomide), and a tracking dye (rhodamine), were conjugated onto single-walled carbon nanotubes (SWCNT). The biodistribution, efficacy, and biocompatibility of these triple functionalized SWCNT were tested in mammalian cells and validated in transparent zebrafish embryos. Results Accumulation of SWCNT-associated nanoconjugates in blastoderm cells facilitated drug delivery applications. Mammalian cell xenograft assays demonstrated that these antiangiogenic SWCNT nanoconjugates specifically inhibited ectopic angiogenesis in the engrafted zebrafish embryos. Conclusion This study highlights the potential of using SWCNT for generating efficient nanotherapeutics.

An open-channel architecture assembly from the [Os3(CO)8{µ-η3-ONCPh(NC5H4)}2] cluster

A novel osmium cluster with an open-channel structure has been synthesised and characterised by X-ray diffraction.

An efficient approach to synthesize glycerol dendrimers via thiol–yne “click” chemistry and their application in stabilization of gold nanoparticles with X-ray attenuation properties

We report here a facile, robust and efficient synthetic approach to glycerol dendrimers in different generations with up to 256 terminal groups, by using a light-mediated thiol–yne “click” reaction and propargylation in an iterative fashion. Neither transition metal nor heating is required during the syntheses. The synthesized first (G1), second (G2) and third (G3) generation dendrimers are well soluble in water and are demonstrated to be nontoxic to HeLa cells. These dendrimers are good organic nanotemplates in the stabilization of gold nanoparticles (AuNPs) in aqueous solution, and a series of narrowly-dispersed AuNPs (d = 1.2–8 nm) were prepared. These AuNPs with good stability exhibit X-ray attenuation properties and thus could be potentially used as computed tomography (CT) contrast agents. In this study, the developed glycerol dendrimers with alkyne or hydroxyl termini would be a good platform for the construction of multifunctional theranostic nanoagents for targeted drug delivery and imaging of diseases.

In vivo spectroscopic photoacoustic imaging of tumor protease activity by using gold nanocage-based activatable nanoprobe

Malignant tumors appear to own the ability to recruit normal tissue cells that contribute to the tumorigenesis process by creating the “tumor microenvironment”. MMPs, is one of the most significant family of proteinases that are related to tumor microenvironment. Recent understanding of MMPs has recognized its role as modulators in tumor microenvironment; however, the current strategies for in vivo MMPs visualization are not competent to provide adequate information with high contrast-to-noise ratio, high spatial resolution and high temporal resolution. In this work, an activatable nano-probe that couples strong plasmonic gold nanocages (GNC) & chromophores to be switched by MMP-2 was selected to improve the visualization of MMP-2 activity by using spectroscopic photoacoustic Imaging (PAI).