Two-dimensional black phosphorus/platinum catalase-like nanozyme-based Fenton reaction-mediated dual-mode immunoassays for the detection of enrofloxacin.

Hydrogen peroxide-based Fenton reaction can effectively degrade many small-molecule fluorescent dyes, leading to notable alterations in fluorescence signals. Additionally, the two-dimensional black phosphorus/platinum nanocomposite (BP/Pt) demonstrates exceptional catalase (CAT) characteristics. Based on these, a colorimetric-fluorescence dual-mode signal output pattern based on BP/Pt-Fenton reaction-rhodamine B tandem reaction system is reported. The physical adsorption property of the BP/Pt nanozymes was utilized to couple with antibodies, thus constructing a novel dual-mode nanozyme-based immuno-sensing assay (NISA). By using the migratory antibiotic enrofloxacin (ENR) as the target, the NISA provided highly sensitive detection with the detection limits of 0.058 ng/mL for colorimetric-mode and 0.025 ng/mL for fluorescence-mode and achieved accurate quantitative detection in environmental water and crucian carp samples. This work provides an innovative design for monitoring antibiotics in the environment and broadens the idea for the application of nanozymes and Fenton systems in immunosensing assays.

Digestibility of Malondialdehyde-Induced Dietary Advanced Lipoxidation End Products and Their Effects on Hepatic Lipid Accumulation in Mice.

Advanced lipoxidation end products (ALEs) are formed by modifying proteins with lipid oxidation products. The health effects of ALEs formed in vivo have been extensively studied. However, the digestibility, safety, and health risk of ALEs in heat-processed foods remain unclear. This investigation was performed to determine the structure, digestibility, and effect on the mice liver of dietary ALEs. The results showed that malondialdehyde (MDA) was able to alter the structure of myofibrillar proteins (MPs) to form linear, loop, and cross-linked types of Schiff bases and dihydropyridine derivatives under simulated heat processing, leading to the intra- and intermolecular aggregation of MPs and, thus, reducing the digestibility of MPs. In addition, dietary ALE intake resulted in abnormal liver function and lipid accumulation in mice. The core reason for these adverse effects was the destructive effect of ALEs on the intestinal barrier. Because the damage to the intestinal barrier leads to an increase in lipopolysaccharide levels in the liver, it induces liver damage by modulating hepatic lipid metabolism.

ZIF-8 sacrificial-templated hollow COF architectures enabled highly efficient enrichment, determination and regulation of food hazards from infant formulas.

Integration of functional micro-/nano-frameworks with various analytical techniques is favored to produce advanced and practical methods for identification, inspection, and regulation of hazards in agro-food products. Herein, two novel synthetic strategies were developed for preparation of core-shell structured ZIF-8@COF by using metal halides as the catalyst, and further construction of hollow-structured covalent organic frameworks (HCOFs) with a sacrificial template method. The HCOFs adsorbent exhibited high stability, universality and adsorption affinity for advanced glycation end products (AGEs) and aflatoxins (AFTs) than pristine COF. Combined with HPLC and HPLC-MS/MS, the applicability of this method was verified by infant formula samples with satisfying recoveries of 87.3%-98.9%. Furthermore, HCOF showed potential ability of adsorbing and removing AGEs from plasma without causing other risk. This work opens up the road for further research on the simple method to synthesis HCOF, besides, provides a technological basis for monitoring and controlling AGEs and AFTs in milk powder.

Detection of ß-lactoglobulin under different thermal-processing conditions by immunoassay based on nanobody and monoclonal antibody.

The problems of inaccurate detection values of thermal-processed ß-lactoglobulin (ß-LG) content seriously affect the screening of allergens. A monoclonal antibody (mAb) against ß-LG was successfully prepared and a highly sensitive sandwich ELISA (sELISA) was constructed with specific nanobody (Nb) as the capture antibody with detection limit of 0.24 ng/mL. Based on this sELISA, the ability of Nb and mAb to recognize ß-LG and ß-LG interacting with milk components was explored. Combined with protein structure analysis to elaborate the mechanism of shielding ß-LG antigen epitopes during thermal-processing, thus enabling the differentiation between pasteurized and ultra-high temperature sterilized milk, the detection of milk content in milk-containing beverages, and the highly sensitive detection and analysis of ß-LG allergens in dairy-free products. The method provides methodological support for identifying the quality of dairy products and reducing the risk of ß-LG contamination in dairy-free products.

Glutathione-Capped CdTe Quantum Dots Based Sensors for Detection of H2O2 and Enrofloxacin in Foods Samples.

Additives and antibiotic abuse during food production and processing are among the key factors affecting food safety. The efficient and rapid detection of hazardous substances in food is of crucial relevance to ensure food safety. In this study, a water-soluble quantum dot with glutathione as a ligand was synthesized as a fluorescent probe by hydrothermal method to achieve the detection and analysis of H2O2. The detection limits were 0.61 µM in water and 68 µM in milk. Meanwhile, it was used as a fluorescent donor probe and manganese dioxide nanosheets were used as a fluorescent acceptor probe in combination with an immunoassay platform to achieve the rapid detection and analysis of enrofloxacin (ENR) in a variety of foods with detection limits of 0.05-0.25 ng/mL in foods. The proposed systems provided new ideas for the construction of fluorescence sensors with high sensitivity.

Exploration of Specific Nanobodies As Immunological Reagents to Detect Milk Allergen of ß-Lactoglobulin without Interference of Hydrolytic Peptides.

Milk proteins are widely used for food supplementation, despite the potential risk of food allergy, especially against ß-lactoglobulin (BLG), which makes BLG surveillance critical. Possible interaction of detecting antibodies with BLG-derived peptides will result in unprecise inspection. Thus, in this study, it was proposed to generate nanobodies (Nbs) and validate the immunological detection of intact BLG rather than hydrolytic peptides. Nbs were successfully retrieved and characterized with high stability and target specificity. A competitive enzyme-linked immunosorbent assay (cELISA) was developed with a linear range from 39 to 10,000 ng/mL and a detection limit (LOD) of 4.55 ng/mL, with a recovery of 86.30%-95.09% revealed by analysis of spiked samples. Meanwhile, a sandwich ELISA (sELISA) was established with Nb82 and BLG polyclonal antibody (pAb-BLG) providing a linear range from 29.7 to 1250 ng/mL and an LOD of 13.82 ng/mL with a recovery of 87.82%-103.97%. The interaction of selected Nbs with BLG-derived peptides was investigated by Nb structure modeling and BLG docking. No binding on hydrolytic peptides was revealed, confirming the precision of Nb-mediated immunoassays. In summary, this study successfully identified BLG-specific Nbs for immunoassay development and guaranteed the monitoring of intact BLG without interference of hydrolytic peptides, providing experimental evidence that our Nbs recognize intact food allergen.