A fluorescent fiber optic biosensor based on allosteric transcription factors (aTFs) for one-step on-site detection of tetracycline and Pb2+

On-site detection of antibiotics and heavy metal ions is critical due to their severe impact on the environment and human health. In this study, allosteric transcription factors (aTFs) were integrated with optical fiber sensing technology to develop a aTF-quantum dot (QD) complex fluorescent fiber biosensor. This biosensor allows for the one-step quantitative on-site detection of tetracycline and Pb 2+ . Within 5   min, the prepared biosensor enabled the quantitative detection of tetracycline and Pb 2+ with detection limits of 16   nM and 0.14   nM, respectively. The linear detection ranges were 10   nM to 1 × 10 6   nM for tetracycline and 0.1   nM to 500   nM for Pb 2+ . The biosensors demonstrated excellent selectivity and could be reused at least five times after regeneration. In actual sample analyses, the biosensors achieved recovery rates of 96.86% to 112.66% for tetracycline and 98.69% to 104.01% for Pb 2+ . These results highlight the advantages of the prepared biosensors, including rapid detection, high sensitivity, and excellent selectivity. Furthermore, a portable water contaminant analyzer platform and corresponding software were developed, significantly enhancing the on-site rapid detection capabilities of optical fiber biosensors. This study reports a novel strategy for constructing optical fiber fluorescent biosensors, making them particularly suitable for field detection applications.