Sensitive detection of live Acinetobacter baumannii with a colorimetric biosensor based on phage tail fiber protein...

While natural phages provide essential host recognition capabilities, their destructive nature often limits utility in diagnostic applications requiring bacterial integrity. Consequently, the phage tail fiber protein (TFP) has emerged as an ideal non-lytic alternative, offering high-affinity binding without the complications of lysis. To further enhance diagnostic performance, we utilized an organic inorganic hybrid nanoflower as a robust carrier.

We engineered a non-lytic, bifunctional organic inorganic hybrid nanoflower by integrating the recombinant phage tail fiber protein (TFP) Gp50 with horseradish peroxidase (HRP) via a one-pot coordination approach. This organic inorganic hybrid nanoflower seamlessly integrates the high-fidelity host recognition of Gp50 with the potent catalytic amplification of HRP, establishing a rapid colorimetric platform for Acinetobacter baumannii. The sensor exhibits a broad linear dynamic range (7.6 × 10³ to 7.6 × 10⁸ CFU/mL) with an exceptionally low detection limit of 46 CFU/mL. Beyond its superior sensitivity, this TFP-based strategy successfully preserves the critical capability of viability discrimination (live/dead bacteria) and offers greater stability and scalability than conventional whole-phage systems.

Given its modularity and ease of mass production, this TFP-nanoflower architecture provides a versatile, robust, and instrument-free solution for the rapid, on-site monitoring of multidrug-resistant pathogens in complex clinical and environmental settings.