Phenylboronic acid-modified magnetic beads combined with DNA-anchored near-infrared AIEgen-based ultrasensitive signal tags for Argonaute-based biosensing

Pathogens have long presented a significant threat to human lives and environmental security, and the rapid detection of infectious pathogens is therefore vital for mitigating such risks. However, the practical application of biosensors is often hampered by complex sample matrices and limited sensitivity. To address these challenges, we established magnetic nanoparticle (MNP) functionalized with phenylboronic acid (PBA) (MNP-PBA) that efficiently and non-destructively captures Staphylococcus aureus ( S. aureus ) from complex samples within 20 min, achieving 92.21% capture rate at 10 8 CFU/mL. In addition, an aggregation-induced emission luminogen, TTQ-PF 6 , was introduced as a detection probe. TTQ-PF 6 exhibits a large Stokes shift (265 nm), intense red fluorescence, and exceptional anti-photobleaching ability—representing a 5.67-fold and 9.40-fold enhancement compared to Rhodamine X, respectively. Moreover, TTQ-PF 6 allows multiple fluorophores to be conjugated to a single DNA strand without the need for chemical reagents. The combination of MNP-PBA and red-emitting TTQ-PF 6 provides strong resistance to matrix interference in bacterial detection, realizing a broad detection linear range for S. aureus from 10 2 to 10 7 CFU/mL, with a limit of detection as low as 13.74 CFU/mL. Overall, this work provides a robust and efficient platform for pathogen detection in complex environments.