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Excessive copper ions (Cu2+) cause serious environmental pollution and even endanger the health of organisms. Fluorescence chemosensing materials are widely used in the detection of metal ions due to their simple operation and high sensitivity. In this study, SiO2-encapsulated single perovskite quantum dot (PQD@SiO2) core-shell nanostructures which show strong, stable, and green fluorescence are synthesized and composited with gold nanoclusters (AuNCs) which show Cu2+-sensitive and red light-emitting fluorescence to obtain a visualized ratiometric fluorescence sensor (AuNCs/PQD@SiO2) for the detection of Cu2+. In the visualized detection of Cu2+, the green fluorescence emitted from the ion-insensitive PQD@SiO2 component is used as a reference signal and the red fluorescence emitted by ion-sensitive AuNC component is adopted as a sensing signal. In the presence of Cu2+, the red fluorescence is quenched whereas the green fluorescence remains stable, which results in a visualized fluorescence color change from orange-red to yellow and finally to green with increasing Cu2+ concentration. The significant change in the fluorescence color of AuNCs/PQD@SiO2 in response to Cu2+ enables a rapid, sensitive, and visualized detection of Cu2+. Further accurate and sensitive ratiometric fluorescence analysis of Cu2+ can be accomplished by measuring the ratio of fluorescence intensities at 643 and 520 nm (I643/I520) at a certain Cu2+ level. The developed AuNCs/PQD@SiO2-based sensor has been validated by its satisfactory application in the detection of Cu2+ in human serum and environmental water samples.

Micro-sized glassy carbon microspheres (GCMs, typically 3 μm in diameter) instead of nano-sized gold nanoparticles (AuNPs, typically 20 nm in diameter) were for the first time used as signal markers for the quantitative detection of antigen such as prostate-specific antigen (PSA). After being treated with concentrated HNO3, GCMs bear carboxyl groups at their surfaces, which enables antibodies to be conjugated with GCMs to yield new type of micro-sized material-based colorimetric probes used for immunochromatographic test strips (ICTSs). The captured black GCMs (with strong and wide-band light absorption) on the T-line of ICTS were used both for qualitative and quantitative determination of PSA. In the case of quantitative determination, a lab-assembled optical strip reader system was used to measure the reflected LED light intensity at 550 nm. The sensing performances of the developed GCM-based ICTSs, such as sensitivity, selectivity, reproducibility, stability, and applicability, were investigated in detail. The developed GCM-based ICTSs can have much higher (3 times) detection sensitivity than AuNP-based ICTSs, showing promising applications in sensitive immunoassay.

Chemically and electrochemically stable conducting films are very desirable in the electrochemical industry and electrochemical sensing. In this work, ethanol was used as the carbon source to synthesize a multilayer-graphene nanosheet (MLGNS) film on ceramic substrates by a catalyst-free chemical vapor deposition (CVD) method at 900 °C and under ambient pressure. The developed CVD method is simple, economical and safe and avoids damage to the graphene nanosheet film during its transfer from the metal substrate to the non-metal substrate. The synthesized MLGNS film was well characterized by various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The prepared MLGNS film has good chemical and electrochemical stability and satisfactory electrical conductivity thus can be used as a new type of electrode material. The MLGNS film on the ceramic substrate has been fabricated into an electrochemiluminescence (ECL) imaging platform to investigate the oxygen reduction reaction (ORR) and evaluate the activities of ORR catalysts, such as PtNPs. The established MLGNS film-based ECL imaging platform may have promising applications in the study of catalysts for fuel cells, high throughput immunoassay in the clinic, and fast screening of anti-cancer drugs.

The proliferation of T cells in peripheral lymphoid tissues requires T cell receptor (TCR)-mediated cell cycle entry. However, the underlying mechanism regulating cell cycle progression in mature T cells is incompletely understood. Here, we have identified an E3 ubiquitin ligase, CRL4

Deregulated NF-κB activation is linked to immunological disorders. Huang et al. revealed CRL4DCAF2 as a negative regulator in controlling NIK stability in DCs. Lower level of DCAF2 is associated with noncanonical NF-κB activation and hyperproduction of IL-23 in psoriasis patients., The E3 ligase CRL4DCAF2 is believed to be a pivotal regulator of the cell cycle and is required for mitotic and S phase progression. The NEDD8-targeting drug MLN4924, which inactivates cullin ring-finger ubiquitin ligases (CRLs), has been examined in clinical trials for various types of lymphoma and acute myeloid leukemia. However, the essential role of CRL4DCAF2 in primary myeloid cells remains poorly understood. MLN4924 treatment, which mimics DCAF2 depletion, also promotes the severity of mouse psoriasis models, consistent with the effects of reduced DCAF2 expression in various autoimmune diseases. Using transcriptomic and immunological approaches, we showed that CRL4DCAF2 in dendritic cells (DCs) regulates the proteolytic fate of NIK and negatively regulates IL-23 production. CRL4DCAF2 promoted the polyubiquitination and subsequent degradation of NIK independent of TRAF3 degradation. DCAF2 deficiency facilitated NIK accumulation and RelB nuclear translocation. DCAF2 DC-conditional knockout mice displayed increased sensitivity to autoimmune diseases. This study shows that CRL4DCAF2 is crucial for controlling NIK stability and highlights a unique mechanism that controls inflammatory diseases., Graphical Abstract