Recent advances in aptamer-based optical and electrochemical biosensors for detection of pesticides and veterinary drugs

Food contaminants are a threat to agriculture, the food chain, and consequently human health. Traditional analytical methods for food safety usually have limitations in achieving quick on-site detection of contaminants in large food samples. Hence, there is an urgent need to develop sensitive, simple, and reproducible methods for the on-site detection of food contaminants. Aptamer-based biosensors have attracted increasing attention owing to their superior performance, simplicity, and sensitivity. Among aptamer-based biosensors, optical and electrochemical biosensors have been constructed for the detection of pesticides and veterinary drugs, such as acetamiprid, organophosphorus pesticides, and various antibiotics, which are together the cause of serious food pollution. Food sample preparation techniques pertaining to testing contaminants in food samples by using those aptasensors are briefly discussed. Additionally, the various nanomaterials and nanocomposites used in the sensing platform are described, to show the good effect of the currently employed means of generating and amplifying sensing signals to improve sensitivity and accuracy of detection. This review provides an overview of the latest advances in the sensing principles of aptamer-based biosensors, such as fluorescent, colorimetric, and electrochemical measurement methods. Recently, using the subsistent aptamers with affinity for food contaminants, optical aptasensors play an important role in detection assays to achieve easier observation and operation with an inexpensive instrument, while electrochemical aptasensors have the advantage of being sensitive, accurate, and less time-consuming. These detection methods provide a meaningful reference for monitoring food safety. The advantages and challenges of aptamer-based biosensors for food contaminant detection are described.