Fc-binding M13 phage-enhanced electrochemical biosensors for influenza virus detection

The importance of in vitro diagnostics (IVDs) has significantly increased, driving the demand for rapid and sensitive diagnostic platforms. Molecular probes play a pivotal role in improving the sensitivity and accuracy of IVDs because of their target-specific signal transduction capabilities. Antibodies, which are commonly used as detection probes, face several challenges, including limited stability, high production costs, and low signal output. In this study, we developed an engineered M13 bacteriophage-based detection system for influenza virus hemagglutinin (HA) using an Electrical ImmunoSorbent Assay (El-ISA). Our design featured Fc-binding motifs on pIII to enable conjugation with target-specific antibodies, along with signal-enhancing biotin modifications on pVIII. The resulting Fc-binding phage probes combined with anti-HA antibodies significantly improved the signal intensity by up to 6.0-fold. This approach enabled the detection of viral proteins in lysate samples at concentrations as low as 44.9 pfu/mL. These findings demonstrated the potential of Fc-binding phage probes as versatile platforms that synergize antibody specificity with enhanced signal transduction. This strategy not only enhances the sensitivity of antibody-based diagnostics but also expands their applicability in diverse research and diagnostic settings.