Magnetic nanozyme-based dual-mode biosensor for highly sensitive detection of Yersinia pestis gene via hybridization chain reaction amplification.

Highly sensitive and accurate detection of Yersinia pestis is critical for effective plague control and biothreat mitigation. Here, we developed a dual-mode colorimetric and fluorescence biosensor based on a multifunctional magnetic nanozyme for Yersinia pestis gene detection, integrating hybridization chain reaction (HCR) for signal amplification and alkaline phosphatase (ALP)-mediated signaling. ALP hydrolyzes adenosine triphosphate (ATP) and L-ascorbic acid-2-phosphate trisodium salt (AA2P) to generate turn-off colorimetric and turn-on fluorescence signals, respectively. The bioassay exhibited good linearity for target genes from 1 pM to 10 nM, with limits of detection of 0.34 pM for colorimetric mode and 0.58 pM for fluorescent mode. It also showed excellent specificity, distinguishing perfectly matched targets from single- and two-base mismatched sequences. Most importantly, the dual-mode platform was successfully applied to spiked human serum samples with satisfactory recoveries. This strategy integrates magnetic separation, signal amplification, and dual-signal output for highly sensitive and specific gene detection, offering great potential for plague monitoring and clinical diagnosis.