Emerging strategies to enhance the sensitivity of competitive ELISA for detection of chemical contaminants in food samples

Chemical contamination in food is one of the most serious food safety problems. Competitive enzyme-linked immunosorbent assay (Cp-ELISA) is the most widely used analytical tool for detection of food chemical contaminants due to its high throughput, low cost, and straightforward readouts. However, conventional ELISA suffers from low sensitivity, which greatly limits its potential in highly sensitive detection. To fulfill increasingly stringent control requirement for chemical contaminants in food, improving the sensitivity of Cp-ELISA is important and meaningful. In this paper, we will briefly review various emerging strategies for increasing Cp- ELISA sensitivity, including: 1) screening higher affinity antibodies to target antigens; 2) preparing competing antigens with lower affinity to antibodies; 3) employing signal amplification; and 4) introducing novel signal transducer elements. This review will focus on clarifying the underlying mechanisms of these strategies in improving sensitivity and providing a careful comparison. Brief discussion on challenges and future directions will be elaborated. (C) 2020 Elsevier B.V. All rights reserved.