Search

The exceptional nature of WO3-x dots has inspired widespread interest, but it is still a significant challenge to synthesize high-quality WO3-x dots without using unstable reactants, expensive equipment, and complex synthetic processes. Herein, the synthesis of ligand-free WO3-x dots is reported that are highly dispersible and rich in oxygen vacancies by a simple but straightforward exfoliation of bulk WS2 and a mild follow-up chemical conversion. Surprisingly, the WO3-x dots emerged as co-reactants for the electrochemiluminescence (ECL) of Ru(bpy)3 2+ with a comparable ECL efficiency to the well-known Ru(bpy)3 2+ /tripropylamine (TPrA) system. Moreover, compared to TPrA, whose toxicity remains a critical issue of concern, the WO3-x dots were ca. 300-fold less toxic. The potency of WO3-x dots was further explored in the detection of circulating tumor cells (CTCs) with the most competitive limit of detection so far.

Semiconducting polymeric carbon nitride (CN) has drawn wide attention ranging from photocatalysis to more recent biosensing owing to unique defect-tolerated optoelectronic properties and being metal-free, cheap, and highly stable. However, at the core of electrical-optical interconversion, the preparation of the CN photoelectrode is still challenging. Now, the growth of CN on electrodes is achieved simply by microwave-assisted condensation in seconds. The ultrafast heating not only addressed the thermodynamic contradiction of precursor volatilization during polymerization but also led to strongly adhesive CN layer on electrodes with gradient carbon-rich texture, greatly accelerating the electron-hole separation and mobility. Consequently, the CN photoelectrode exhibited a remarkable photocurrent and a record cathodic efficiency of electrochemiluminescence up to 7 times that of benchmark Ru(bpy)3 Cl2 in aqueous solution.

Surpassing natural enzymes in cost, stability and mass production, nanozymes have attracted wide attention in fields from disease diagnosis to tumor therapy. However, nanozymes intrinsically have low reaction selectivity, which significantly restricts their broad applications. Here we report a general method to address this challenge by following a biomimetic operation principle of substrates channeling and screening. Two oxidase- and peroxidase-like nanozymes, i.e., emerging N-doped carbon nanocages and Prussian blue nanoparticles, were cascaded as a proof of concept to improve the reaction selectivity in transforming the substrate into the targeted product against the interferences by more than 2000 times. The cascaded nanozymes were also adopted to a spatially confined microfluidic device, leading to more than 100-fold enhancement of the reaction efficiency due to signal amplification. Beyond the structured matters, we highlight the general utility of the operation principle in biology to endow nanozymes with remarkable selectivity and efficiency as well simplicity.

Aflatoxin B1 (AFB1 ), one of the most toxic mycotoxins, is classified as a group I carcinogen and ubiquitous in various foods and agriproducts. Thus, accurate and sensitive determination of AFB1 is of great significance to meet the criteria of food safety. Direct detection of AFB1 is difficult by monoclonal antibody (mAb) with large molecular size (≈150 kD) since the target is too small to produce a detectable signal change. Herein, by combining the electrochemical properties of nanomaterials and the advantages of nanobodies, we developed a direct, highly selective and sensitive electrochemical immunosensor for small molecule detection. The proposed immunosensor had a wide calibration range of 0.01 to 100 ng mL-1 and a low detection limit of 3.3 pg mL-1 (S/N=3). Compared with the immunosensor prepared with mAb which was applied in the typical indirect immunoassay, the immunosensor in this work possessed two orders of magnitudes wider linear range and 10-fold more sensitivity. The as-obtained immunosensor was further successfully applied for sensing AFB1 in real samples. This proposed assay would provide a simple, highly sensitive and selective approach for the direct immunoassay of small molecule AFB1 , and is extendable to the development of direct immunosensing systems for other small molecules detection by coupling nanocarbon and nanobody.

Photocatalyst-assisted degradation of organic pollutants, which exhibits a novel strategy for solar-energy utilization, possesses enormous potential in various applications. Extending the light-absorption range in the spectrum of sunlight and improving light-conversion efficiency are always primary issues to enhance the catalytic performance of these photocatalysts. Herein, a new structure of gold-nanorod-decorated TiO2 rambutan-like microspheres is designed, which exhibits superior photocatalytic ability toward Rhodamine B in the range of visible light due to the 3D distribution of the TiO2 branches on the surface of the microspheres, which prompts the multireflection of photons. The absorption rate of photons is thereby tremendously enhanced. This is beneficial for the generation of hot electrons originating from the localized surface plasmonic resonance of Au nanorods, which can be used to both initiate the reaction and produce the photothermal effect. Hot electrons generated by a single Au nanorod in microspheres to initiate the degradation reaction can be as high as 2.5 times of those in the nanowires' counterpart. Moreover, the heating power of a single Au nanorod in microspheres reaches up to 4.4 times higher than that in nanowires, which further accelerates the degradation rate. The reaction pathway of visible-light-assisted RhB degradation catalyzed by Au/TiO2 microspheres goes through an initial N-deethylation process instead of the complete cycloreversion catalyzed by pure TiO2 microspheres under UV irradiation. This strategy of structure design for improved photon absorption, which achieves high degradation rate and photothermal effect, is promising for the development of novel photocatalysts.

The global tobacco epidemic is still a devastating threat to public health. Toxic reactive oxygen species (ROS) in the cigarette smoke cannot be efficiently eliminated by currently available cigarette filters. The resultant oxidative stress causes severe lung injury and further diseases. To tackle this challenge, herein, a novel copper tannic acid coordination (CuTA) nanozyme is reported as a highly active and thermostable ROS scavenger. The CuTA nanozyme exhibits intrinsic superoxide dismutase-like activity, catalase-like activity, and hydroxyl radical elimination capacity. These synergistic antioxidant abilities make the CuTA nanozyme a promising candidate for the improvement of commercial cigarette filters. Mouse model results show that commercial cigarettes loaded with CuTA nanozyme efficiently scavenge ROS in the cigarette smoke, reduce oxidative stress-induced lung inflammation, and minimize the resultant acute lung injury. The developed CuTA nanozyme offers an efficient ROS scavenger with multiple antioxidant ability and opens up new opportunities for the modification of cigarette filters to reduce the toxic effects of cigarette smoke.

Metal-doped mesoporous composites were synthesised by using a facile one-pot sol–gel approach. Special multifunctional surfactants were designed and used simultaneously as structure-directing agents, N-doped carbon source and metal dopant. This versatile profile of properties is obtained by combining complex metallate anions carrying dicyanamide ions as ligands with nitrogen-containing amphiphilic counteranions. Furthermore, also the use of nonamphiphilic countercations yields interesting precursors that can be converted into carbon materials with submicron-sized morphologies by simple annealing. We therefore present herein a novel precursor system enabling immediate pathways to new materials that are of significant interest for sustainable catalysis and energy applications.

We propose a simple but efficient, rapid, and quantitative ion-responsive micelle system based on counter-anion exchange of a surfactant with an imidazolium unit. The ion-exchange reaction results in the amphiphilic-to-hydrophobic transition of the imidazolium salt, leading to the destruction of the micelles, which has been successfully applied to controlled release and emulsification. The proposed design offers a novel alternative stimulus to control these smart physical aggregates besides pH, temperature and light-with extra advantages. Our finding greatly benefits both fundamental research and industry.