One-step assay of pore-forming biotoxins based on biomimetic perovskite nanocrystals.

[Display omitted] • A biomimetic CsPbBr 3 NCs-based signal probe was designed for the detection of pore-forming toxins in complex media. • One-step quantitation of pore-forming toxins with dual-readout signals was realized. • A novel signal transduction strategy was proposed to exploit the utility of CsPbBr 3 NCs in biosensing field. • The assay has been successfully applied to detect the overall secreted pore-forming biotoxin in the life cycle of E. coli. As one of the emerging inorganic materials, perovskite nanocrystals (NCs) have inspired the development of various optoelectronic applications in recent years; however the effective utilization in biomedical fields is still limited. Herein, we report a quantitative measurement of broad-spectrum pore-forming toxins in complex media based on biomimetic CsPbBr 3 NCs. Specifically, by coating CsPbBr 3 NCs with phospholipid (CsPbBr 3 NCs@PL), the outer micelle membrane can not only serve as a shell to protect the stability of CsPbBr 3 NCs, but also interact with broad-spectrum biotoxins. Meanwhile, toxin-triggered transmembrane pore formation can cause water permeation, which breaks down the structure of CsPbBr 3 NCs@PL, generating striking fluorescent and electrochemical dual responses. Therefore, direct quantitative measurements of biotoxins are realized via dual-readout signals with inverse change trend, resulting in a detection limit of 50 nM. Our report represents the first example of CsPbBr 3 NCs for the develpment of biosensors. Meanwhile, such a label-free, cost-effective and widely applicable biomimetic CsPbBr 3 NCs@PL may present a valuable tool for the detection of biotoxin infections, and overcomes the limitations of perovskite materials in biosensing. [ABSTRACT FROM AUTHOR]