A colorimetric chemosensor for sensitive and selective detection of copper(II) ions based on catalytic oxidation of 1-naphthylamine.

Rapid on-site detection of copper(II) ions (Cu) with high sensitivity and selectivity is of great significance in the safety monitoring of drinking water and food. Colorimetric detection is a robust fast determination method with the main drawback of low sensitivity. Herein, we developed a colorimetric chemosensor based on a colored polymer product.

Modulation of plasmonic chiral shell growth on gold nanorods nonchiral surfactants.

Recently, in combination with seed-mediated growth, thiolated chiral molecule-guided growth has shown great promise in obtaining chiral plasmonic nanostructures. Previously, with the assistance of chiral cysteines (Cys), we realized helical growth of plasmonic shells on gold nanorod (AuNR) seeds dispersed in cetyltrimethylammonium bromide (CTAB) solution. Herein, we further studied the roles of non-chiral cationic surfactants in tuning the helical growth.

Gold-Nanoparticle-Based Chiral Plasmonic Nanostructures and Their Biomedical Applications.

As chiral antennas, plasmonic nanoparticles (NPs) can enhance chiral responses of chiral materials by forming hybrid structures and improving their own chirality preference as well. Chirality-dependent properties of plasmonic NPs broaden application potentials of chiral nanostructures in the biomedical field. Herein, we review the wet-chemical synthesis and self-assembly fabrication of gold-NP-based chiral nanostructures.

Bottom-Up Synthesis of Helical Plasmonic Nanorods and Their Application in Generating Circularly Polarized Luminescence.

Chiral growth and chirality transfer associated with plasmonic nanostructures have rejuvenated the field of chirality. As the precise regioselective growth of inorganic crystals into chiral shapes at the nanoscale is extremely challenging, "bottom-up" synthesis of intrinsically chiral nanoparticles with structural stability is obviously attractive and important. With the thiolated bimolecular cosurfactants, we demonstrated a chemical strategy for the synthesis of intrinsically helical plasmonic nanorods (HPNRs) with strong and tailorable plasmonic circular dichroism (PCD) responses, deriving from the zwitterionic interactions between the -NH and -COO groups of the cysteine molecules (Cys).

Improving peroxidase activity of gold nanorod nanozymes by dragging substrates to the catalysis sites via cysteine modification.

Surface chemistry control is a key means to improve substrate selectivity and enhance catalytic activity of nanozymes, a kind of novel artificial enzymes. Herein, we demonstrated that apart from chemical properties of functional groups, their spatial distance to the catalytic sites is also very important to improve the catalytic performance of nanozymes. Using cetyltrimethylammonium bromide (CTAB) coated gold nanorods (AuNR) as the example, we showed that cysteine (Cys) surface modification can greatly enhance the peroxidase activity of AuNR for the oxidation of substrate 3,3',5,5'-tetramethylbenzidine (TMB).

Constructing chiral gold nanorod oligomers using a spatially separated sergeants-and-soldiers effect.

A sergeants-and-soldiers (S&S) effect is very useful to the fabrication of supramolecular chirality. This strategy has not yet been explored in the construction of chiral plasmonic superstructures. Herein, we demonstrate a spatially separated S&S effect in fabricating plasmonic superstructures and modulating their chiroptical responses.

Gold Nanorod-Based Nanoplatform Catalyzes Constant NO Generation and Protects from Cardiovascular Injury.

Cardiovascular disease is a leading cause of death, and one of the effective therapeutic strategies for cardiovascular disease is to provide a controlled, constant supply of nitric oxide (NO) in a mild manner; however, this has proved challenging in the clinic. To address this problem, we built a nitric oxide synthase (NOS)-like nanoplatform (NanoNOS) that consists of a noble metal nanoparticle core and a mesoporous silica shell and demonstrated the ability of NanoNOS to catalyze production of NO . Mechanistic studies show that the catalysis consists of a three-step reaction: the oxidation of NADPH to produce O oxidase-like activity and the subsequent dismutation of O to HO SOD-like activity, followed by HO-mediated oxidation of l-arginine to produce NO a nonenzymatic pathway.

Enhanced type I photoreaction of indocyanine green via electrostatic-force-driven aggregation.

Owing to the strong NIR absorbance, indocyanine green (ICG) has attracted new attention in emerging photo-theranostics. However, ICG has a very low ROS production efficiency and mainly works through the type II photoreaction via its monomer. The aggregation tendency of ICG in aqueous milieus further worsens the scenario.

Initiation of protective autophagy in hepatocytes by gold nanorod core/silver shell nanostructures.

The high reactivity of silver nanoparticles leads to their broad applications in the anti-bacterial field; however, the safety of silver nanoparticles has attracted increasing public attention. After exposure to silver nanoparticles in vivo, the liver serves as their potential deposition site; however the potential biological effects of such nanoparticles on hepatocytes at low dosages are not well understood. Here, we study the interaction between gold nanorod core/silver shell nanostructures (Au@Ag NRs) and human hepatocytes, HepG2 cells, and determine that Au@Ag NRs at sub-lethal doses can induce autophagy.

Plasmon-Enhanced Oxidase-Like Activity and Cellular Effect of Pd-Coated Gold Nanorods.

Local surface plasmon resonance (LSPR)-enhanced catalysis has attracted much attention recently. Palladium nanoparticles have been reported to have various nanozyme activities and exhibit promising potentials for biomedical applications. However, as Pd is a poor plasmonic metal, little attention has been paid to its LSPR-regulated nanozyme activity.