Photoactive Covalent Organic Framework-Modulated Zinc–Air Battery Self-Powered Biosensor for Detecting Hemagglutinin Protein of H1N1 Influenza Virus

Self-powered electrochemical sensor based on a zinc-air battery has gained wide attention for its good stability and high energy density, making it a promising platform for disease markers detection. However, the large overpotential of the oxygen reduction reaction (ORR) limits its output signal, posing great challenges for practical applications. In this work, a self-powered electrochemical sensor based on a photoassisted zinc-air battery (PZAB-SPES) was proposed to specifically and sensitively detect hemagglutinin (HA) proteins of the H1N1 influenza virus. Two kinds of covalent organic frameworks (COFs) with different linker lengths were designed and modified on the electrode surface to reduce the overpotential of the ORR efficiently. Using the COF with excellent photocatalytic ORR performance as photocathode material and MnO₂ as signal transduction unit, the output potential of the sensor was as high as 1.64 V. In the presence of HA protein, enzymatic etching reaction was triggered, during which abundant ascorbic acid was generated to etch MnO₂ on the electrode, thereby reducing the output signal of PZAB-SPES. The proposed PZAB-SPES achieved ultrasensitive determination of HA protein from 100 fg/mL to 10 ng/mL with a low detection limit of 52 fg/mL. In addition, the PZAB-SPES was further applied to detect HA protein of influenza virus in nasopharyngeal swab specimens of infected people, demonstrating great application prospect for the early diagnosis of infectious diseases.