A Programmable Plug-and-Play Sensing Platform for Ultrasensitive Detection via Adaptive Supramolecular Assembly

The development of a versatile and programmable sensing platform is crucial for advancing intelligent diagnostics and environmental monitoring. Herein, we present a plug-and-play, polypeptoid-based sensing platform capable of rapid and accurate detection of multiple analytes, exemplified by dipicolinic acid (DPA) and tetracycline (TC). This platform integrates a polypeptoid–lanthanide ion ratiometric fluorescent probe with highly efficient magnetic bacterial enrichment, achieving over 90% capture efficiency even in complex environments. The system exhibits a linear response to DPA concentrations ranging from 0 to 4.5 μM, with a detection limit as low as 5.73 nM, surpassing many existing biosensors. Coupling with portable devices further enables real-time quantification and continuous monitoring of bacterial spores over a wide range of 101–108 CFU/mL, with a significantly low detection limit of 4.47 CFU/mL within 10 min. Further, the structural programmability of the platform allows functional adaptation, as demonstrated by a notably low TC detection limit = 11.21 nM. This work offers a general strategy for constructing multifunctional diagnostic tools, addressing key limitations of traditional biosensors in terms of target diversity and field applicability.