Adsorption-stage phage biosensors for foodborne bacteria detection: mechanisms, engineering strategies, and perspectives.
The rapid and specific detection of foodborne bacteria in complex matrices remains a critical analytical challenge. Conventional nucleic acid amplification and immunological methods offer high analytical sensitivity, but they often provide limited information on bacterial viability because nucleic acids and antigenic epitopes may persist after cell death. As obligate parasites, bacteriophages (phages) initiate infection through the adsorption stage, relying on highly specific recognition between tail proteins and host receptors. This early interaction provides a rapid recognition window before signals from downstream replication or lysis become dominant. Herein, this review presents a systematic overview of biosensors based on the bacteriophage adsorption stage for the detection of foodborne bacteria developed over the past five years. It explores how whole phages and their derived proteins can serve as biorecognition elements in combination with different transducers for bacterial capture and signal transduction, with emphasis on interface-oriented immobilization, signal attribution, matrix effects, and adaptation to point-of-care testing (POCT), especially lateral flow assays (LFAs) for instrument-free analysis. Meanwhile, it highlights that whole phages retain the native adsorption architecture and may support interpretation of viability when appropriate validation models are used, whereas phage-derived proteins provide more flexible recognition modules for interface design and signal generation but require attention to effective avidity, conformational context, and consistency between batches. Furthermore, future phage-based analytical platforms are discussed in relation to time-resolved kinetic validation, computationally assisted readout, and adsorption-coupled detection and containment.