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The discovery of the bone-gut axis linking bone metabolism to gut microbiota (GM) dysbiosis has revolutionized our understanding of managing degenerative skeletal diseases. Targeting GM regulation has emerged as a promising approach to osteoporosis treatment. Herein, we develop propolis nanoemulsions (PNEs) with enhanced gastrointestinal stability and oral bioavailability for GM-based osteoporosis therapy. Orally administered PNEs exhibit superior antiosteoporosis efficacy in an ovariectomized (OVX) mouse model by modulating the GM structure and metabolites and restoring the intestinal barrier function. Multiomics analysis reveals that a reduction in Streptococcus abundance and an increase in the GM metabolite l-arginine are key factors in osteoporosis management. These changes suppress osteoclast activity and enhance osteoblast function, leading to balanced bone remodeling and, thus, significant antiosteoporotic effects via the gut-bone axis. Our results deepen insights into the intricate relationship between GM and bone remodeling, suggesting a promising strategy that maintains the homeostasis of the GM structure and metabolite for osteoporosis treatment.

Valleytronics, i.e., the manipulation of the valley degree of freedom, offers a promising path for energy-efficient electronics. One of the key milestones in this field is the room-temperature manipulation of the valley information in thick-layered material. Using scanning photocurrent microscopy, we achieve this milestone by observing a geometrically dependent circular photocurrent in a few-layer molybdenum disulfide (MoS 2 ) under normal incidence. Such an observation shows that the system symmetry is lower than that of bulk MoS 2 material, preserving the optical chirality-valley correspondence. Moreover, the circular photocurrent polarity can be reversed by applying electrical bias. We propose a model where the observed photocurrent results from the symmetry breaking and the built-in field at the electrode-sample interface. Our results show that the valley information is still retained even in thick-layered MoS 2 at room temperature and opens up new opportunities for exploiting the valley index through interface engineering in multilayer valleytronics devices.

Psoriasis is a chronic inflammatory disease whose etiology is directly related to the dysregulation of cutaneous immune homeostasis. However, how to finely modulate the skin immune microenvironment to restore homeostasis remains an important challenge. Inspired by the natural attribute of tumor exosomes in the immune escape, the tumor-derived exosomes as an active targeting nanoplatform for the effective treatment of inflammatory skin disorder were first reported. As keratinocytes and immune cells express high PD-1 during the onset of psoriasiform skin inflammation, the PD-L1-positive exosomes derived from melanoma cells carrying pristimerin with extremely anti-inflammatory potential were yielded to treat psoriasis. The PD-L1 + exosomes carrying pristimerin were characterized, and the cellular uptake was performed to evaluate the PD-1 target capability. The anti-inflammatory action of PD-L1 + exosomes carrying pristimerin was observed in both in vitro and in vivo models of psoriasis. Our exosomes substantially increased pristimerin uptake with CD4 + T cells and keratinocytes, significantly inhibited the proliferation of Th17 cells, and promoted Treg differentiation in a psoriasis-like model. Obviously, PD-L1 + exosomes carrying pristimerin significantly and safely reversed imiquimod (IMQ)-induced psoriasis in mice, indicated by reducing epidermal thickness, decreasing plaque formation, and suppressed excessive inflammatory response, due to its dual targeting of both CD4 + T cells and keratinocytes gathering around the lesion. The inflammatory cell infiltration and pro-inflammatory cytokine production in psoriasis were suppressed by our engineered exosomes. Besides, PD-L1 + exosomes carrying pristimerin treatment alleviated ferroptosis-related changes in psoriatic skin, thereby dampening excessive inflammation and, in turn, decreasing the abnormal proliferation of keratinocytes in psoriatic lesions. This study demonstrates that our engineered exosomes can not only act as a treat-to-target strategy for psoriasis treatment but also provide insight in clinical application of inflammatory disorders.

Perovskites have been studied because of their adjustable wavelength range, high color purity, and wide color gamut. However, they still face some problems such as poor stability and insufficient infrared luminescence. The perovskite glass can improve the stability and luminescence properties of the perovskite. In this paper, a highly stable CsPb 1- x Er x Br 3 -ZBLAN fluoride glass with mid-infrared and visible light emission was prepared. The ZBLAN fluoride glass has good inertness, which can improve the stability of the CsPb 1- x Er x Br 3 perovskite. The CsPb 1- x Er x Br 3 -ZBLAN fluoride glass can prevent the perovskite from being destroyed by water, oxygen, and laser. The Er 3+ replaces Pb 2+ to bond with Br - to become the luminescent center of the CsPb 1- x Er x Br 3 -ZBLAN perovskite glass, which extends the luminescence to the mid-infrared region. In addition, its luminescent intensity is significantly higher than those of the ZBLAN-Er glass and CsPb 1- x Er x Br 3 perovskite. After irradiation with a 365 nm UV lamp for 13 h, the luminescence intensity of the CsPb 1- x Er x Br 3 -ZBLAN perovskite glass decreases only by 10%. The EDS spectrum shows that the elements of the CsPb 1- x Er x Br 3 perovskite are uniformly distributed in the glass matrix. The X-ray diffraction spectrum shows that the sample has both the CsPb 1- x Er x Br 3 perovskite phase and the glass phase. This indicates that CsPb 1- x Er x Br 3 is well crystallized in the ZBLAN glass matrix. The three parameters calculated by the Judd-Ofelt theory show that the CsPb 1- x Er x Br 3 perovskite can increase the covalency and asymmetry around the rare earth ion Er 3+ . The transmission electron microscope can clearly see the morphological structure of the CsPb 1- x Er x Br 3 perovskite in the ZBLAN glass matrix. The infrared Fourier transform spectroscopy shows that the sample has lower phonon energy. This proves that the sample has good infrared luminescence characteristics. Finally, the visible and infrared light sources were prepared. Under the irradiation of the 365 nm ultraviolet lamp and 980 nm laser, the perovskite glass produces green light and infrared emission.

Diacetoxyscirpenol (DAS) is a type A trichothecene mycotoxin with low molecular weight, and with respect to its toxicity and the occurrence in food and feed, it is known as a potential risk for public and animal health. In the present study, first, a sensitive and specific monoclonal antibody (5E7) was developed. Then, the antibody was applied to develop a competitive-type pressure-dependent immunosensor (CTPDI). The Au@PtNP was synthesized and labeled with goat antimouse antibody (Au@PtNPs-IgG). Finally, the concentration of DAS was negatively correlated with the pressure signal. In the presence of optimal conditions, matrix-matched calibration curves were plotted for wheat samples, in which an optimal IC50 value (half maximal inhibitory concentration) of 3.08 ng/g was achieved. The CTPDI was further applied to detect natural and blind wheat samples, and validation was carried out by liquid chromatography-tandem mass spectrometry. The results showed that CTPDI was highly appropriate and accurate for detection of DAS in wheat.

Atomically thin magnets are the key element to build up spintronics based on two-dimensional materials. The surface nature of two-dimensional ferromagnet opens up opportunities to improve the device performance efficiently. Here, we report the intrinsic ferromagnetism in atomically thin monolayer CrBr 3 , directly probed by polarization resolved magneto-photoluminescence. The spontaneous magnetization persists in monolayer CrBr 3 with a Curie temperature of 34 K. The development of magnons by the thermal excitation is in line with the spin-wave theory. We attribute the layer-number-dependent hysteresis loops in thick layers to the magnetic domain structures. As a stable monolayer material in air, CrBr 3 provides a convenient platform for fundamental physics and pushes the potential applications of the two-dimensional ferromagnetism.

We describe a new fluorescence turn-on sensor for homogeneous detection of aflatoxin B1 (AFB1), a potent low molecular weight mycotoxin. A key innovation is the binding-induced intramolecular interaction involving the following two sets of probes: (1) a gold nanoparticle (AuNP) immobilized with hundreds of assistant oligonucleotides (AO) and dozens of anti-AFB1 monoclonal antibodies, and (2) the AFB1-BSA (BSA = bovine serum albumin) antigen conjugated with fluorophore-labeled signal oligonucleotides (SO) that contained a short sequence complementary to AO. Specific binding of AFB1-BSA to the antibody brought the fluorophore very close to the surface of the AuNP through a stable intramolecular hybridization between AO and SO, resulting in efficient quenching of fluorescence. The improved fluorescence quenching substantially reduced the background, due to the binding-induced intramolecular hybridization, and improved the signal-to-background ratio by 390%. In the presence of AFB1 in a sample, competitive binding of AFB1 in the sample to the antibodies immobilized on the AuNP caused the release of the fluorophore-labeled AFB1-BSA from the AuNP, turning on fluorescence. A detection limit of 2.3 nM was achieved, which meets the requirement for AFB1 detection at regulatory levels. Analyses of rice samples using this assay showed recoveries of 86-102%. Incorporating appropriate antibody probes could extend the assay to the detection of other small molecules.

To ensure protein beverage safety and prevent illegal melamine use to artificially increase protein content, a rapid, on-site, ultrasensitive detection method for melamine must be developed because melamine is detrimental to human health. Herein, an ultrasensitive time-resolved fluorescence detection paper (TFDP) was developed to detect melamine in protein beverages within 15 min using a one-step sample preparation. The lower limits of detection were 0.89, 0.94, and 1.05 ng/mL, and the linear ranges were 2.67-150, 2.82-150, and 3.15-150 ng/mL (R 2 > 0.982) for peanut, walnut, and coconut beverages, respectively. The recovery rates were 85.86-110.60% with a coefficient of variation <7.80% in the spiking experiment. A high specificity was observed in the interferent experiment. When detecting real protein beverage samples, the TFDP and ultraperformance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) results were consistent. This method is a promising alternative for rapid, on-site detection of melamine in beverages.

Aflatoxins and zearalenone (ZEN) are highly common mycotoxins in maize and maize-based products. This study aimed to report a time-resolved fluorescence immunochromatographic assay (TRFICA) developed using two idiotypic nanobodies for rapid, quantitative, and simultaneous detection of aflatoxin B 1 (AFB 1 ) and ZEN in maize and its products. A novel Eu/Tb(III) nanosphere with enhanced fluorescence was prepared as a label and conjugated to anti-idiotypic nanobody (AIdnb) and monoclonal antibody (mAb). On the basis of nanosphere-antibody conjugation, two patterns of competitive time-resolved strip methods (AIdnb-TRFICA and mAb-TRFICA) were established and compared. The half inhibition concentration of AIdnb-TRFICA was 0.46 and 0.86 ng·mL -1 for AFB 1 and ZEN, which was 18.3- and 20.3-fold more sensitive than that of mAb-TRFICA for AFB 1 and ZEN, respectively. Under optimal conditions, AIdnb-TRFICA for dual mycotoxin was established and provided a quantitative relationship ranging from 0.13 to 4.54 ng·mL -1 for AFB 1 and 0.20 to 2.77 ng·mL -1 for ZEN, with a detection limit of 0.05 and 0.07 ng·mL -1 in the buffer solution, respectively. AIdnb-TRFICA showed good recoveries (72.6%-106.6%) in samples and was applied to detect dual mycotoxin in maize samples with satisfying results. To the best of our knowledge, it is the first report about a time-resolved strip method based on AIdnbs for dual mycotoxin.

Immunochromatographic (IC) assays are considered suitable diagnostic tools for the determination of mycotoxins. A europium nanospheres-based time-resolved fluorescence immunoassay (Eu-Nano-TRFIA), based on a monoclonal antibody and a portable TRFIA reader, was developed to determine total aflatoxin (including aflatoxins B1, B2, G1, and G2) levels in feed samples. Under optimized conditions, the Eu-Nano-TRFIA method detected total aflatoxin within 12 min. It showed good linearity (R(2) > 0.985), LOD of 0.16 μg/kg, a wide dynamic range of 0.48-30.0 μg/kg, recovery rates of 83.9-113.9%, and coefficients of variation (CVs) of 3.5-8.8%. In the 397 samples from company and livestock farms throughout China, the detection rate was 78.3%, concentrations were 0.50-145.30 μg/kg, the highest total aflatoxin content was found in cottonseed meal, and corn was found to be the most commonly contaminated feed. This method could be a powerful alternative for the rapid and ultrasensitive determination of total aflatoxin in quality control and meet the required Chinese maximum residue limits.

Aflatoxins are a group of extremely toxic small molecules that have been involved in human hepatic and extrahepatic carcinogenesis as causative agents. Herein, we developed a real-time immuno polymerase chain reaction (IPCR) assay for the accurately quantitative detection of aflatoxins in agri-products base on a M13 phage containing aflatoxin anti-idiotypic nanobody and its encoding DNA which was used to design the specific primers. The limit of detection (LOD) of the assay is 0.02 ng/mL, which exhibits a 4-fold improvement over traditional phage ELISA. The developed method was successfully validated with the samples of corn, rice, peanut, and feedstuff, which are major aflatoxin-contaminated agri-products. And the recoveries were from 77.05 to 122.16%. For further validation, the developed assay was also compared with a reference HPLC method for the analysis of aflatoxins in corn and peanuts, and concordant results (R(2) = 0.991) were obtained. In this context, this study provides a novel opportunity to analyze aflatoxins in agri-products.

A phage-displayed library of variable domain of heavy chain of the heavy chain antibody (VHH) or nanobody (Nb) was constructed after immunizing an alpaca with aflatoxin B1 (AFB1) conjugated with bovine serum albumin (AFB1-BSA). Two AFB1-specific nanobodies were selected. The obtained nanobodies were compared to an aflatoxin-specific monoclonal antibody B5 with respect to stability under organic solvents and high temperature. The two nanobodies could bind antigen specifically after exposure to temperatures as high as 95 °C. Besides, the nanobodies showed better or similar tolerance to organic solvents. A competitive ELISA with nanobody Nb26 was developed for the analysis of AFB1, exhibiting an IC50 value of 0.754 ng/mL (2.4 μM), linear range from 0.117 to 5.676 ng/mL. Due to the high tolerance to methanol, sample extracts were analyzed by nanobody-based ELISA without dilution. The recovery from spiked peanut, rice, corn and feedstuff ranged from 80 to 115%. In conclusion, the isolated nanobodies are excellent candidates for immunoassay application in aflatoxin determination.