Highly Sensitive Immunochromatographic Identification of Tetracycline Antibiotics in Milk.

N A Taranova,A V Zherdev,V V Shmanai,B B Dzantiev,E A Zvereva,A S Kruhlik,D A Semyonov,I I Vashkevich,S A Eremin

doi:10.1155/2015/347621

Abstract

A rapid immunochromatographic assay was developed for the control of tetracycline (TC). The assay is based on the competition between immobilized TC-protein conjugate and TC in a tested sample for binding with polyclonal anti-TC antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. Conjugation of colloidal gold and the total immunoglobulin (IgG) fraction of polyclonal antibodies was used to increase the assay sensitivity to ensure low content of specific antibodies in the conjugate. This allowed effective inhibition of free TC and conjugate binding in the strip test zone. Photometric marker registration allows control of the reduction of binding, thereby enhancing detection sensitivity. The proposed assay allows TC to be detected at concentrations up to 20 ng/mL, exceeding the limit of detection of the known analogues, in a wide working range (more than two orders) of 60 pg/mL to 10 ng/mL, ensured through the use of polyclonal antibodies. The assay time is 10 min. The efficiency of the designed assay is shown to identify TC in milk; the degree of recovery of TC ranges from 90 to 112%. The precision of the concentrations measurements was no more than 10%.

Highlights

Tetracyclines (TCs) are a group of broad-spectrum antibiotics representing polyketones in their chemical structure [1]
Characteristics of immunoreagents included in the test systems included determination of the composition of hapten-protein synthesized conjugate and assessment of the interaction of the conjugate and polyclonal antibodies
The developed IC test system is characterized by a low detection threshold of TC in milk of 0.02 ng/mL for instrumental recording, as well as a wide operating range

Summary

Introduction

Tetracyclines (TCs) are a group of broad-spectrum antibiotics representing polyketones in their chemical structure [1]. TCs are widely used in veterinary medicine, both for therapeutic and preventive purposes, due to their high activity towards a large number of Gram-positive and Gramnegative bacteria, small doses, and broad spectrum of action. The most widely used tetracycline antibiotics are tetracycline (TC), chlortetracycline, and oxytetracycline (Figure 1). Because of their intensive and diverse uses, tetracyclines may enter the human body in the treatment of diseases and with food. This can cause toxic and allergic effects, dysfunction of the gastrointestinal tract, renal insufficiency, and deformation of mucous tissues [5, 6]. It is important to monitor the presence of tetracyclines and other antibiotics in food

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