An accurate and ultrasensitive ratiometric electrochemical aptasensor for determination of Ochratoxin A based on catalytic hairpin assembly

Recent advances in ratiometric electrochemical sensors for food analysis

Ratiometric electrochemical sensors are renowned for their dual-signal processing capabilities, enabling automatic correction of background noise and interferences through built-in calibration, thus providing more accurate and reproducible measurements. This characteristic makes them highly promising for food analysis. This review comprehensively summarizes and discusses the latest advancements in ratiometric electrochemical sensors and their applications in food analysis, emphasizing their design strategies, detection capabilities, and practical uses. Initially, we explore the construction and design strategies of these sensors. We then review the detection of various food-related analytes, including nutrients, additives, metal ions, pharmaceutical and pesticide residues, biotoxins, and pathogens. The review also briefly explores the challenges faced by ratiometric electrochemical sensors in food testing and potential future directions for development. It aims to provide researchers with a clear introduction and serve as a reference for the design and application of new, efficient ratiometric electrochemical sensors in food analysis.

A label-free ratiometric homogeneous electrochemical aptasensor based on dual catalytic hairpin self-assembly for rapid and sensitive detection of ochratoxin A in food

The food contamination with Ochratoxin A (OTA) has highlighted the need to create precise, sensitive, and convenient techniques. Herein, we proposed a label-free and immobilization-free ratiometric homogeneous electrochemical aptasensor based on dual catalytic hairpin self-assembly (CHA) for OTA detection. Methylene blue (MB) and ferrocene (Fc) in solution were utilized as label-free signaling molecules, generating a response signal (IMB) and a reference signal (IFc), respectively. The ratio of IMB/IFc was utilized as a measure to quantify OTA. Dual CHA was exploited to increase the ratiometric signal and enhance the amplification efficiency. This aptasensor achieved trace-level detection for OTA over a linear range of lower concentrations (1.0 × 10-3 ng/mL-1.0 × 103 ng/mL) with LOD of 92 fg/mL. The aptasensor was successfully applied to detect OTA in cereal and wine, with comparable results of HPLC-MS/MS. This strategy provided a viable platform for rapid, sensitive, and accurate detection of OTA in food.

Signal amplification strategy of DNA self-assembled biosensor and typical applications in pathogenic microorganism detection

Biosensors have emerged as ideal analytical devices for various bio-applications owing to their low cost, convenience, and portability, which offer great potential for improving global healthcare. DNA self-assembly techniques have been enriched with the development of innovative amplification strategies, such as dispersion-to-localization of catalytic hairpin assembly, and dumbbell hybridization chain reaction, which hold great significance for building biosensors capable of realizing sensitive, rapid and multiplexed detection of pathogenic microorganisms. Here, focusing primarily on the signal amplification strategies based on DNA self-assembly, we concisely summarized the strengths and weaknesses of diverse isothermal nucleic acid amplification techniques. Subsequently, both single-layer and cascade amplification strategies based on traditional catalytic hairpin assembly and hybridization chain reaction were critically explored. Furthermore, a comprehensive overview of the recent advances in DNA self-assembled biosensors for the detection of pathogenic microorganisms is presented to summarize methods for biorecognition and signal amplification. Finally, a brief discussion is provided about the current challenges and future directions of DNA self-assembled biosensors.

Recent Advances in Electrochemical Biosensors for Food Control

The rapid and sensitive detection of food contaminants is becoming increasingly important for timely prevention and treatment of foodborne disease. In this review, we discuss recent developments of electrochemical biosensors as facile, rapid, sensitive, and user-friendly analytical devices and their applications in food safety analysis, owing to the analytical characteristics of electrochemical detection and to advances in the design and production of bioreceptors (antibodies, DNA, aptamers, peptides, molecular imprinted polymers, enzymes, bacteriophages, etc.). They can offer a low limit of detection required for food contaminants such as allergens, pesticides, antibiotic traces, toxins, bacteria, etc. We provide an overview of a broad range of electrochemical biosensing designs and consider future opportunities for this technology in food control.