A Robust Homogeneous Fluorescence Polarization Immunoassay for Rapid Determination of Erythromycin in Milk

Recent Advances in Pretreatment Methods and Detection Techniques for Veterinary Drug Residues in Animal-Derived Foods

Veterinary drugs are extensively employed in livestock, poultry, and aquaculture, playing a crucial role in preventing and treating animal diseases, facilitating growth, and enhancing feed conversion rates. Nevertheless, veterinary drug residues in animal-derived foods pose a direct or potential threat to human life and health. Precise detection of these residues in animal-derived foods to ensure their safety has become an important mission. In this review, we sum up the current progress of applied pretreatment methods and detection techniques for veterinary drug residues in animal-derived foods. At present, sample pretreatment methods mainly consist of the following: liquid-liquid extraction; solid-phase extraction; immunoaffinity chromatography; Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method; and molecular imprinting technology. Detection techniques mainly involve chromatographic techniques, immunoassay techniques, fluorescence polarization immunoassay, and surface-enhanced Raman scattering. We also discussed the advantages and limitations of these technologies. Moreover, we point out the development direction and tendency of detection techniques in the future, providing references for the detection of veterinary drug residues in animal-derived foods.

Construction of a portable and sensitive electrochemical immunosensor for the rapid detection of erythromycin based on semiconductive bimetallic MOF

The sensitive determination of antibiotics in food products is vital for ensuring food safety and protecting human health. Herein, we have fabricated a novel electrochemical portable and sensitive electrochemical immunosensor for the efficient detection of erythromycin (ERY) containing in food stuffs. For this, a semiconductive cooper/ferric bimetallic metal-organic framework (scMOF), which was synthesized using 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) as linking ligand (denoted as CuxFe3-x(HHTP)2), was utilized simultaneously as the platform for anchoring antibody and for modifying the sprinted printed electrode (SPE) to construct the electrochemical immunosensor. The obtained scMOF, CuxFe3-x(HHTP)2, exhibited high porosity, promoted conductivity, and enhanced anchoring ability toward antibody. Thereby, the developed SPE immunosensor demonstrated the superior biosensing performance for the detection of ERY. Within a wide range from 1.0 fg mL-1 to 1.0 ng mL-1, the CuxFe3-x(HHTP)2-based portable SPE immunosensor had an ultralow detection limit of 0.69 fg mL-1, together with high selectivity, good reproducibility, and excellent long-term stability, as well as acceptable practicality. The present SPE immunosensor based on scMOFs not only provides an innovative biosensing strategy for the sensitive inspection of antibiotics, but also extends the application of scMOF in the field of food analysis.

Portable smartphone-assisted amperometric immunosensor based on CoCe-layered double hydroxide for rapidly immunosensing erythromycin

Herein, we have manufactured a newly designed bifunctional impedimetric and amperometric immunosensor for rapidly detecting erythromycin (ERY) in complicated environments and food stuffs. For this, bimetallic cobalt/cerium-layered double hydroxide nanosheets (CoCe-LDH NSs), which was derived from Co-based zeolite imidazole framework via the structure conversion, was simultaneously utilized as the bioplatform for anchoring the ERY-targeted antibody and for modifying the gold and screen printed electrode. Basic characterizations revealed that CoCe-LDH NSs was composed of mixed metal valences, enrich redox, and abundant oxygen vacancies, facilitating the adhesion on the electrode, the antibody adsorption, and the electron transfers. The manufactured impedimetric and amperometric immunosensor based on CoCe-LDH has showed the comparable sensing performance, having a wide linear detection range from 1.0 fg mL-1 to 1.0 ng mL-1 with the ultralow detection limit toward ERY. Also, the portable, visualized, and efficient analysis of ERY was then attained at the smartphone-assisted CoCe-LDH-based SPE.

Detection of Dibutyl Phthalate in Surface Water by Fluorescence Polarization Immunoassay

Dibutyl phthalate (DBP) is widely used as a plasticizer in the production of polymeric materials to give them flexibility, strength and extensibility. However, due to its negative impact on human health, in particular reproductive functions and fetal development, the content of DBP must be controlled in food and the environment. The present study aims to develop a sensitive, fast and simple fluorescence polarization immunoassay (FPIA) using monoclonal antibodies derived against DBP (MAb-DBP) for its detection in open waters. New conjugates of DBP with various fluorescein derivatives were obtained and characterized: 5-aminomethylfluorescein (AMF) and dichlorotriazinylaminofluorescein (DTAF). The advantages of using the DBP-AMF conjugate in the FPIA method are shown, the kinetics of binding of this chemical with antibodies are studied, the analysis is optimized, and the concentration of monoclonal antibodies is selected for sensitivity analysis-16 nM. The calibration dependence of the fluorescence polarization signal for the detection of DBP was obtained. The observed IC50 (DBP concentration at which a 50% decrease in the fluorescence polarization signal occurs, 40 ng/mL) and the limit of detection (LOD, 7.5 ng/mL) values were improved by a factor of 45 over the previously described FPIA using polyclonal antibodies. This technique was tested by the recovery method, and the high percentage of DBP discovery in water ranged from 85 to 110%. Using the developed method, real water samples from Lake Onega were tested, and a good correlation was shown between the results of the determination of DBP by the FPIA method and GC-MS. Thus, the FPIA method developed in this work can be used to determine DBP in open-water reservoirs.

Immunotechniques for the Group Determination of Macrolide Antibiotics Traces in the Environment Using a Volume-Mediated Sensitivity Enhancement Strategy

Macrolide antibiotics, which are effective antimicrobial agents, are intensively used in human and veterinary medicine, as well as in agriculture. Consequently, they are found all over the world as environmental pollutants, causing harm to sensitive ecological communities and provoking a selection of resistant forms. A novel azithromycin derivative, which was used as hapten conjugate, ensured the group immunorecognition of six major macrolide representatives (105-41%), namely erythromycin, erythromycin ethylsuccinate, clarithromycin, roxithromycin, azithromycin, and dirithromycin in a competitive immunoassay based on anti-clarithromycin antibodies. The heterologous hapten-based ELISA format resulted in a 5-fold increase in sensitivity, with an IC50 value of 0.04 ng/mL for erythromycin. In this study, we proposed an underexploited strategy in an immunoassay field to significantly improve the detectability of analytes in environmental samples. Unlike most approaches, it does not require special enhancers/amplifiers or additional concentration/extraction procedures; instead, it involves analyzing a larger volume of test samples. A gradual volume increase in the samples (from 0.025 to 10 mL) analyzed using a direct competitive ELISA, immunobeads, and immunofiltration assay formats based on the same reagents resulted in a significant improvement (more than 50-fold) in assay sensitivity and detection limit up to 5 and 1 pg/mL, respectively. The suitability of the test for detecting the macrolide contamination of natural water was confirmed by the recovery of macrolides from spiked blank samples (71.7-141.3%). During 2022-2023, a series of natural water samples from Lake Onega and its influents near Petrozavodsk were analyzed, using both the developed immunoassay and HPLC-MS/MS. The results revealed no contamination of macrolide antibiotic.

Recent Advances in the Determination of Veterinary Drug Residues in Food

The presence of drug residues in food products has become a growing concern because of the adverse health risks and regulatory implications. Drug residues in food refer to the presence of pharmaceutical compounds or their metabolites in products such as meat, fish, eggs, poultry and ready-to-eat foods, which are intended for human consumption. These residues can come from the use of drugs in the field of veterinary medicine, such as antibiotics, antiparasitic agents, growth promoters and other veterinary drugs given to livestock and aquaculture with the aim of providing them as prophylaxis, therapy and for promoting growth. Various analytical techniques are used for this purpose to control the maximum residue limit. Compliance with the maximum residue limit is very important for food manufacturers according to the Food and Drug Administration (FDA) or European Union (EU) regulations. Effective monitoring and control of drug residues in food requires continuous advances in analytical techniques. Few studies have been reviewed on sample extraction and preparation techniques as well as challenges and future directions for the determination of veterinary drug residues in food. This current review focuses on the overview of regulations, classifications and types of food, as well as the latest analytical methods that have been used in recent years (2020-2023) for the determination of drug residues in food so that appropriate methods and accurate results can be used. The results show that chromatography is still a widely used technique for the determination of drug residue in food. Other approaches have been developed including immunoassay, biosensors, electrophoresis and molecular-based methods. This review provides a new development method that has been used to control veterinary drug residue limit in food.