Homogeneous fluorescence immunoassay based on AuNPs (AgNPs) quenching multicolor QDs@hydrogel beads for the simultaneous ultra-sensitive determination of aflatoxin B1 and capsaicinoids in food.

A capsaicinoids (CPCs) broad spectrum monoclonal antibody with same recognition ability to capsaicin (CPC), dihydrocapsaicin (DCPC), nordihydrocapsaicin (NDCPC), and N-vanillylnonanamide (NV) is prepared. Chitosan (CS) hydrogel is used as the carrier of multicolor quantum dots (QDs) to prepare fluorescence hydrogel beads, CPCs and aflatoxin B1 (AFB1) antibody are coupled with fluorescence hydrogel beads to prepare signal probes. Using AuNPs (or AgNPs) as fluorescence quenching agent to prepare quenching probes followed forming a fluorescence quenching test system. Based on optimal group of signal and quenching probes, a novel, simple, convenient, and ultra-sensitive homogeneous fluorescence immunoassay for the simultaneous detection of CPCs and AFB1 is constructed. The limit of detection (LOD) of assay for AFB1 and CPC is 0.00064 µg L-1 and 0.00049 µg L-1, respectively. This method can realize the simultaneous rapid detection of AFB1 and CPCs in food, which provides a new strategy for the identification of kitchen waste oil.

Efficient degradation of orange II by core shell CoFe2O4-CeO2 nanocomposite with the synergistic effect from sodium persulfate.

Novel core shell CoFe2O4-CeO2 (CoFe-Ce) nanocomposite was synthesized and investigated as an efficient photocatalyst to activate sodium persulfate (Na2S2O8, PS) for orange Ⅱ (OⅡ) degradation. The CoFe-Ce nanocomposite was successfully designed and synthesized by a facile hydrothermal reaction followed by calcination and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), and vibrating sample magnetometer (VSM). Compared with pure CoFe2O4 and CeO2, the photocatalytic efficiency of CoFe-Ce nanocomposite was significantly improved. Under the irradiation of visible light, the catalytic degradation efficiency of orange II could reach to 98.5% within 60 min. Additionally, the as-prepared material could be recycled for at least five times using magnetic separation ability of the nanocomposite, and during the cycling the dye degradation rate was almost unchanged. The active species produced during the degradation were studied by classical quenching experiments, and the different types of free radicals produced in the system were further confirmed by electron paramagnetic resonance (EPR) spectroscopy. This novel nanocomposite is expected to have potential application for degradation of organic pollutants in wastewater by utilizing solar energy.

Docetaxel prodrug and hematoporphyrin co-assembled nanoparticles for anti-tumor combination of chemotherapy and photodynamic therapy.

To realize the synergistic anti-tumor effect of chemotherapy and photodynamic therapy, the mono sulfide-modified docetaxel (DTX) prodrugs (DSD) provided by our laboratory and hematoporphyrin (HP) were used to physically prepare co-assembled nanoparticles (DSD/HP NPs) by nano-precipitation. For the first time, this study showed its characteristics, in vitro anti-tumor activity, pharmacokinetic behavior in rats, in vivo distribution, and pharmacodynamic effects on 4T1 tumor-bearing Bal b/c mice. DSD/HP NPs optimized by single-factor and response surface optimization had several distinct characteristics. First, it had dark purple appearance with particle size of 105.16 ± 1.24 nm, PDI of 0.168 ± 0.15, entrapment efficiency and drug loading of DSD and HP in DSD/HP NPs of 96.27 ± 1.03% and 97.70 ± 0.20%, 69.22 ± 1.03% and 20.03 ± 3.12%, respectively. Second, it had good stability and could release DTX and HP slowly in the media of pH 7.4 PBS with 10 mM DTT (H2O2). Moreover, DSD/HP NPs along with NiR treatment significantly inhibited 4T1 cells proliferation, and induced more reactive oxygen species and cells apoptosis. In vivo pharmacokinetic and pharmacodynamic studies showed that DSD/HP NPs could prolong the drug circulation time in rats, increase drug distribution in tumor site, obviously inhibit tumor growth, and decrease the exposure of drug to normal tissues. Therefore, DSD/HP NPs as a promising co-assembled nano-drug delivery system could potentially improve the therapeutic efficiency of chemotherapeutic drug and achieve better anti-tumor effects due to the combination of chemotherapy and photodynamic therapy.

Visible-light-driven activation of sodium persulfate for accelerating orange II degradation using ZnMn2O4 photocatalyst.

A special catalytic system was obtained by using ZnMn2O4 (ZMO) materials to activate Na2S2O8 and catalytically degrade organic dye orange II under visible light irradiation. The ZMO nanoparticles were prepared by a simple one-step method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). In this study, the ZMO/Na2S2O8 system was used to degrade orange II, and the degradation rate reached 97.44% in 60 min. ZMO catalysts could be recycled for at least five times, and its degradation rate was only decreased by 1.84%. The free radicals produced during the degradation of orange II were studied by classical quenching experiments, and the different types of free radicals produced in the system were further confirmed by electron paramagnetic resonance (EPR) spectroscopy. The catalytic degradation of orange II in this system was mainly caused by the production of superoxide, sulfate and hydroxyl radicals, which achieved high degradation.