Development of bacteriophage-modified europium alginate beads for rapid screening of Escherichia coli

Escherichia coli is a common bacterium that can contaminate food and water, leading to infections. Traditional detection methods like PCR and ELISA, while accurate, require specialized equipment and take time. This study aimed to develop a fast and effective biosensor to detect E. coli in liquids. The biosensor is based on bacteriophage-modified europium alginate beads. These beads were fabricated using an extrusion drop method, followed by a two-step EDC/NHS process to immobilize E. coli bacteriophages on the surface. To enhance the photoluminescence intensity, 1,10-phenanthroline (Phen) was added to the fabrication process. The biosensor achieved a low detection limit of 37 CFU·mL^-1 with a response time of 30 min. It accurately detected E. coli in bottled water and apple juice, with non-linear correlations between bacterial concentrations (10¹-10⁶ CFU·mL^-1) and luminescence intensity. Additionally, the biosensor demonstrated consistent performance across production batches, showing high specificity and selectivity in detecting target bacteria. This pioneering one-time-use bacteriophage-based biosensor significantly advances the rapid and specific detection of E. coli in liquid samples.