Chungang Wang

Colorimetric Detection of Pb2+ Using Glutathione Functionalized Gold Nanoparticles

A facile, cost-effective and sensitive colorimetric detection method for Pb(2+) has been developed by using glutathione functionalized gold nanoparticles (GSH-GNPs). The sensitivity and selectivity of detection were investigated in detail. The GSH-GNPs could be induced to aggregate immediately in the presence of Pb(2+), especially after the addition of 1 M NaCl aqueous solution. The Pb(2+) could be detected by colorimetric response of GNPs that could be monitored by a UV-vis spectrophotometer or even naked eyes, and the detection limit could reach 100 nM. The GSH-GNPs bound by Pb(2+) showed excellent selectivity compared to other metal ions (Hg(2+), Mg(2+), Zn(2+), Ni(2+), Cu(2+), Co(2+), Ca(2+), Mn(2+), Fe(2+), Cd(2+), Ba(2+), and Cr(3+)), which led to prominent color change. This provided a simple and effective colorimetric sensor (no enzyme or DNA) for on-site and real-time detection of Pb(2+). Most importantly, this probe was also applied to determine the Pb(2+) in the lake samples with low interference and high sensitivity.

L-cysteine functionalized gold nanoparticles for the colorimetric detection of Hg2+ induced by ultraviolet light

A simple, cost-effective yet rapid and sensitive colorimetric sensor for the detection of Hg(2+) using L-cysteine functionalized gold nanoparticles induced by ultraviolet radiation was developed. The sensitivity and selectivity of detection was also investigated. The L-cysteine modified gold nanoparticles can be induced to aggregate quickly in the presence of Hg(2+), especially with the assistance of ultraviolet radiation. The presence of Hg(2+) can be monitored by the colorimetric response of gold nanoparticles. The detection of Hg(2+) could be realized, after measuring the UV-vis spectra, with a detection limit of 100 nM. The selectivity of this method has been investigated by other divalent metal ions. The effective colorimetric sensor can be used for on-site and real-time Hg(2+) detection.

Uniform hollow mesoporous silica nanocages for drug delivery in vitro and in vivo for liver cancer therapy

In this article, we report the fabrication of monodisperse hollow mesoporous silica (HMS) nanocages with uniform size possessing a hollow cubic core and mesoporous shell with penetrating pore channels based on a template-coating-etching process. It is worthwhile noting the obtained HMS nanocages with cubic void space and highly porous shell endow the structures with much higher storage capacity and sustained release of anticancer drugs. More importantly, the therapeutic efficacy of doxorubicin-loaded HMS nanocages was evaluated in vitro and in vivo for liver cancer therapy. The results show that the doxorubicin-loaded HMS nanocages have good cell uptake and can induce efficient cell deathinvitro. Taken together, this study demonstrates that the biocompatible HMS nanocages can effectively deliver drugs to the tumors and suppress tumor growth compared to free doxorubicinin vivo. Additionally, the synthetic strategy has also extended to fabrication of the uniform and monodisperse HMS nanocapsules with spherical shape.

Multifunctional hollow mesoporous silica nanocages for cancer cell detection and the combined chemotherapy and photodynamic therapy.

Highly uniform and multifunctional hollow mesoporous silica nanocages that combined excellent properties (good biocompatibility, fluorescence imaging, drug delivery, and dual-mode cancer therapy) in one single system were synthesized. Dye molecules labeled in the nanocages could be used as traceable detectors in fluorescence imaging. A chemotherapeutic drug, doxorubicin (DOX), has been loaded into the nanocages with a high storage capacity due to the large cubic cavities and could be released through the penetrating mesoporous channels in a sustained fashion. Hematoporphyrin molecules were also covalently doped in the nanocages and allowed for photodynamic therapy. More importantly, a cooperative, synergistic therapy combining chemotherapy and photodynamic therapy exhibited high therapeutic efficacy for cancer therapy in vitro.

General Route to Multifunctional Uniform Yolk/Mesoporous Silica Shell Nanocapsules: A Platform for Simultaneous Cancer‐Targeted Imaging and Magnetically Guided Drug Delivery

Hollow mesoporous SiO(2) (mSiO(2)) nanostructures with movable nanoparticles (NPs) as cores, so-called yolk-shell nanocapsules (NCs), have attracted great research interest. However, a highly efficient, simple and general way to produce yolk-mSiO(2) shell NCs with tunable functional cores and shell compositions is still a great challenge. A facile, general and reproducible strategy has been developed for fabricating discrete, monodisperse and highly uniform yolk-shell NCs under mild conditions, composed of mSiO(2) shells and diverse functional NP cores with different compositions and shapes. These NPs can be Fe(3)O(4) NPs, gold nanorods (GNRs), and rare-earth upconversion NRs, endowing the yolk-mSiO(2) shell NCs with magnetic, plasmonic, and upconversion fluorescent properties. In addition, multifunctional yolk-shell NCs with tunable interior hollow spaces and mSiO(2) shell thickness can be precisely controlled. More importantly, fluorescent-magnetic-biotargeting multifunctional polyethyleneimine (PEI)-modified fluorescent Fe(3)O(4)@mSiO(2) yolk-shell nanobioprobes as an example for simultaneous targeted fluorescence imaging and magnetically guided drug delivery to liver cancer cells is also demonstrated. This synthetic approach can be easily extended to the fabrication of multifunctional yolk@mSiO(2) shell nanostructures that encapsulate various functional movable NP cores, which construct a potential platform for the simultaneous targeted delivery of drug/gene/DNA/siRNA and bio-imaging.

Tailored Synthesis of Octopus‐type Janus Nanoparticles for Synergistic Actively‐Targeted and Chemo‐Photothermal Therapy

A facile, reproducible, and scalable method was explored to construct uniform Au@poly(acrylic acid) (PAA) Janus nanoparticles (JNPs). The as-prepared JNPs were used as templates to preferentially grow a mesoporous silica (mSiO2 ) shell and Au branches separately modified with methoxy-poly(ethylene glycol)-thiol (PEG) to improve their stability, and lactobionic acid (LA) for tumor-specific targeting. The obtained octopus-type PEG-Au-PAA/mSiO2 -LA Janus NPs (PEG-OJNP-LA) possess pH and NIR dual-responsive release properties. Moreover, DOX-loaded PEG-OJNP-LA, upon 808 nm NIR light irradiation, exhibit obviously higher toxicity at the cellular and animal levels compared with chemotherapy or photothermal therapy alone, indicating the PEG-OJNP-LA could be utilized as a multifunctional nanoplatform for in vitro and in vivo actively-targeted and chemo-photothermal cancer therapy.

Multifunctional fluorescent-magnetic polyethyleneimine functionalized Fe3O4-mesoporous silica yolk-shell nanocapsules for siRNA delivery.

A facile, mild, environmentally friendly and reproducible strategy was used to fabricate the multifunctional fluorescent-magnetic polyethyleneimine functionalized Fe(3)O(4)-mesoporous silica yolk-shell nanocapsules for simultaneous fluorescent tracking and magnetically guided small interfering RNA delivery.

Selected-control synthesis of monodisperse Fe3O4@C core-shell spheres, chains, and rings as high-performance anode materials for lithium-ion batteries.

A method is reported for the first time for the selected-control, large-scale synthesis of monodispersed Fe(3)O(4)@C core-shell spheres, chains, and rings with tunable magnetic properties based on structural evolution from eccentric Fe(2)O(3)@poly(acrylic acid) core-shell nanoparticles. The Fe(3)O(4)@C core-shell spheres, chains, and rings were investigated as anode materials for lithium-ion batteries. Furthermore, a possible formation mechanism of Fe(3)O(4)@C core-shell chains and rings has also been proposed.

Optical DNA detection based on gold nanorods aggregation.

Sequence-specific DNA detection is important in various biomedical applications such as gene expression profiling, disease diagnosis and treatment, drug discovery and forensic analysis. Herein, the localized surface plasmon resonance properties of unmodified gold nanorods (GNRs) in 1 mM cetyltrimethyl-ammonium bromide solution were used for sensing DNA sequences, with good simplicity and sensitivity. The intensity of typical plasmon resonance absorption bands of the GNRs decreased with increasing cDNA concentration. The detection of a 30-mer single-stranded oligonucleotide as a model reached a detection limit of about 0.1 pM. This study will be significant for as-prepared GNRs for future application in biological systems.

Controllable colours and shapes of silver nanostructures based on pH: application to surface-enhanced Raman scattering

This paper reports for the first time that the shape of silver nanostructures on quartz slides, from a nanoprism to a nanodisc, can be easily realized within a few minutes simply by adjusting the pH value of the immersion solution. Different colours of the quartz slide covered with Ag nanostructures appeared, from deep blue to yellow, corresponding to the shapes of Ag nanostructures changing from nanoprisms to nanodiscs. Surface-enhanced Raman scattering (SERS) activities of the silver nanoprisms and nanodiscs (obtained through adjusting the pH values) were checked using p-aminothiophenol (p-ATP) as a probe molecule at both near-infrared (1064 nm) and visible light (514.5 nm) excitation. The results obtained further confirmed the enhancement mechanism of SERS based on the coupling between the surface plasmon resonance (SPR) of the substrates and the laser excitation wavelength. This work will be of great significance in understanding the SERS enhancement mechanism and in the fabrication of nanoparticle films for biosensing.