Colorimetric Aptasensor Based on Bimetallic Single-Atom Nanozyme and Self-Selected Aptamers for Ultrasensitive Detection of Quarantine Plant Viruses

Quarantine plant viruses (QPV) pose significant economic and environmental threats, yet their efficient and sensitive detection remains a major challenge. Herein, a sandwich colorimetric aptasensor strategy has been proposed based on a bimetallic single-atom nanozyme (FeCo-NC) and self-selected aptamers for the on-site detection of Tomato mosaic virus (ToMV), a prevalent QPV. The dual active centers of FeCo-NC significantly enhance the efficient activation of H₂O₂. Simultaneously, FeCo-NC serves as an excellent carrier for aptamers due to its large surface area and high porosity. Aptamers obtained through SELEX exhibit high efficiency and specificity in recognizing ToMV, ensuring high selectivity of the sensor. Moreover, a 96-well plate format enables high-throughput detection, enhancing detection efficiency. The sensor exhibits a low detection limit of 1.4 pg/mL and a wide linear range of 10–10⁷ pg/mL. Compared with traditional detection methods, this sensing is highly versatile, making it valuable for plant disease monitoring and environmental protection.