Bimetallic iron-copper nanozyme for determination and degradation of norfloxacin in foods.

Iron-copper nanozymes (Fe-Cu NZs) with good peroxidase activity were prepared through hydrothermal method by using copper nitrate as copper source, iron acetate as iron source and 2, 5-dihydroxyterephthalic acid as organic ligand. Upon oxidation of the colourless TMB to light blue products by Fe-Cu NZs, the addition of Norfloxacin (NOR) resulted in a colour change to dark blue. The absorbance of the system correlated linearly with NOR concentration in the range of 3.

Impact of internal metal ions in tea polysaccharides on antioxidant potential and suppression of cancer cell growth.

Four kinds of tea polysaccharides (MBTPS, MGTPS, ZBTPS, ZGTPS) were extracted from Maofeng black tea, Maofeng green tea,Ziyan black tea and Ziyan green tea, and then four tea polysaccharides (RMBTPS, RMGTPS, RZBTPS, RZGTPS) after metal removal were prepared. The physicochemical properties, antioxidant activity and inhibitory activity on cancer cell proliferation of the above polysaccharides were studied. The composition analysis shows that these tea polysaccharides were glycoproteins complexes, composed of a variety of monosaccharides, and the removal of metal ions did not lead to fundamental changes in the composition of polysaccharides.

Novel colorimetric detection of oxytetracycline in foods by copper nanozyme.

In this study, copper nanozyme (CuNZs) possess good laccase-like activity were synthesized by grinding method with cupric chloride dihydrate as copper source, sodium borohydride as reducing agent and β-cyclodextrin as protective agent. The CuNZs can oxidize colorless 2,4-dinitrophenol (2,4-DP) to red product. When oxytetracycline (OTC) was added to the above three solutions, the color changed from red to orange and the absorbance increased again, indicating that OTC was also an affinity substrate for CuNZs.

Antioxidant and hypoglycemic activity of tea polysaccharides with different degrees of fermentation.

Four polysaccharides (GTPS, OTPS, BTPS and DTPS) were extracted from green tea, oolong tea, black tea and dark tea respectively. The physical and chemical properties, antioxidant and hypoglycemic activities were studied. Structural analysis showed that these tea polysaccharides were glycoprotein complexes, and there were significant differences in microstructure, protein, total sugar and uronic acid content.

MoSe nanoparticle with ROS scavenging and multi-enzyme activity for the treatment of DSS-induced colitis in mice.

Ulcerative colitis (UC), as a most common inflammatory bowel disease (IBD), has become a global public health concern. Exploring novel method of treating UC is urgent and necessary. Recently, nanozyme with excellent antioxidant properties may be one useful therapeutic strategy.

A dual-mode optical assay for iron(II) and gallic acid based on Fenton reaction.

The hydroxyl radicals (·OH) produced by the Fenton reaction of iron(II) and hydrogen peroxide (H O ) can oxidize the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized TMB (Ox-TMB), resulting in a decrease in the fluorescence intensity of the reaction system and an increase in ultraviolet absorption. Ox-TMB had a visible absorption peak at 625 nm and a fluorescence peak around 420 nm. When gallic acid (GA) was added to the system, Ox-TMB was reduced to TMB, which made the color of the system disappear and the fluorescence recover.

A colorimetric and fluorescence dual-signal determination for iron (II) and HO in food based on sulfur quantum dots.

A colorimetric and fluorescence dual-signal method based on sulfur quantum dots (SQDs) was established for determination of iron (II) (Fe) and HO in foods. Due to the complexation of Fe with SQD, Fe can cause fluorescence quenching of SQDs, and the color of the mixed solution changed from light yellow to deep green. By use of Fenton reaction, HO can restore the quenched fluorescence of SQDs, and the color of the mixture changed from green to colorless.

A colorimetric and fluorescence turn-on probe for the detection of ascorbic acid in living cells and beverages.

A colorimetric and fluorescence turn-on dual-signal assay was developed for the determination of ascorbic acid (AA). Because the ultraviolet absorption of the oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB) overlapped with the fluorescence emission of glutathione stabilized Au nanoclusters (AuNCs), the fluorescence of AuNCs can be quenched by oxTMB. When AA was added, the blue oxTMB was reduced to colorless TMB, and the fluorescence of AuNCs was restored simultaneously.

Colorimetric and turn-on fluorescence determination of mercury (II) by using carbon dots and gold nanoparticles.

A colorimetric and turn-on fluorometric assay with high sensitivity and selectivity is described for the optical detection of mercury (II) ions (Hg), based on carbon dots with -SH (SN-CDs) and gold nanoparticles (AuNPs). On addition of Hg, the color of the system (SN-CDs/AuNPs) changes from red to blue. A new absorption peak appears at 700 nm, and its absorbance increases with the concentration of Hg, while at 530 nm, the absorbance of AuNPs decreases.

Green and high-yield synthesis of carbon dots for ratiometric fluorescent determination of pH and enzyme reactions.

In this work, the carbon dots (CDs) were prepared by one-pot hydrothermal method with chitosan as a carbon source and hydrogen peroxide as an oxidant, this route is a novel, simple and green. The prepared CDs has a relatively high photoluminescence (PL) quantum yield (QY) (18.9%) and good water solubility.

Nitrogen-doped carbon dots from rhizobium as fluorescence probes for chlortetracycline hydrochloride.

Fluorescent nitrogen-doped carbon dots (CDs) were prepared via hydrothermal method at 190 °C for 10 h using rhizobium from soy as the carbon and nitrogen source. Their optical properties, structure, morphology, and functional groups were characterized in detail and the results showed that they possess unique excitation-dependent fluorescence behavior, with average diameter 4.5 ± 2.

Ratiometric fluorescence assay for L-Cysteine based on Fe-doped carbon dot nanozymes.

In this work, a ratiometric fluorescence method based on nanozyme was fabricated to determine L-Cysteine. Taking silkworm feces as a carbon source, together with Fe, Fe-doped carbon dots (Fe-CDs) were synthesized through a hydrothermal method. Fe-CDs were able to oxidize the enzyme substrate o-phenylenediamine (OPD) to produce oxidized OPD (Ox-OPD) when HO coexisted with them.

A ratiometric fluorometric ciprofloxacin assay based on the use of riboflavin and carbon dots.

Carbon dots (CDs) were hydrothermally synthesized from selenious yeast. They were further coupled with riboflavin to form a dually emitting probe for ciprofloxacin (CIP). Under 370 nm excitation, the probe displays dual (blue and green) emissions with peaks at 443 and 510 nm.

Rose-like Nanocomposite of Fe-Ni Phosphides/Iron Oxide as Efficient Catalyst for Oxygen Evolution Reaction.

In order to accelerate the reaction rate of water splitting, it is of immense importance to develop low-cost, stable and efficient catalysts. In this study, the facile synthesis of a novel rose-like nanocomposite catalyst (Ni P/Fe P/Fe O ) is reported. The synthesis process includes a solvothermal step and a phosphatization step to combine iron oxides and iron-nickel phosphides.

Rosmarinic acid counteracts activation of hepatic stellate cells via inhibiting the ROS-dependent MMP-2 activity: Involvement of Nrf2 antioxidant system.

Recently, oxidative stress is involved in hepatofibrogenesis. Matrix metalloproteinase-2 (MMP-2) is required for activation of hepatic stellate cells (HSCs) in response to reactive oxygen species (ROS). This study was designed to explore the hypothesis that the inhibitory effect of rosmarinic acid (RA) on HSCs activation might mainly result from its antioxidant capability by increasing the synthesis of glutathione (GSH) involved in nuclear factor kappa B (NF-κB)-dependent inhibition of MMP-2 activity.

[Expression of platelet-derived growth factor receptor α and its ligand PDGF- A in breast cancer].

Aim: To investigate the potential significance of platelet-derived growth factor receptor-α (PDGFR-α) and platelet-derived growth factor A (PDGF-A) expression in mammary carcinomas, and analyze its correlation with the lymph node metastasis and the expression of PDGF-A.

Methods: Used immunohistochemistry to detect the protein expression of PDGFR-α and PDGF-A in paraffinembedded breast carcinomas.

Results: The expression of PDGFR-α and PDGF-A were observed in 51.