Peptide nanodots-bridged metal-organic framework (PNMOF): Intelligently design a cascade amplification platform for smartphone-facilitated mobile fluorescence imaging detection of pyrethroids

Within this study, a peptide nanodots-bridged metal–organic framework (PNMOF) has been constructed by predictably assembling highly efficient fluorescent dipeptide nanodots into the three-dimensional framework upon coordination of Zn(II) and dihydroxamate linkers. The established system was on behalf of a new class of tripartite hybrid material, i.e., metal ion, organic linker, and peptide nanodot, which integrated the chemical and structural versatility in a modular fashion. Owing to its unique open framework with tripartite construction, PNMOF exhibited a rapid and sensitive response, therefore, the target (e.g., lambda-cyhalothrin, LCY) driven into the tripartite hybrid structure stimulated a cascade amplification effect. LCY can cause significant fluorescence quenching in the PNMOF-based cascade amplification platform due to the charge transfer mechanism, which was confirmed by density functional theory calculations. PNMOF-based cascade amplification platform was employed for fluorescence imaging detection of pyrethroids in solution and solid state assisted by the smartphone. The limit of detection was as low as 0.34 μg/L and the recoveries percentage in real agricultural products was calculated as 88.26–108.17%. This work not only underlies the structural diversity of conventional metal–organic framework but also offers a useful tool in environmental protection and food safety.