Single Particle-Based Confocal Laser Scanning Microscopy for Visual Detection of Copper Ions in Confined Space

摘要

Main observation and conclusion A single particle-based confocal laser scanning microscopy was developed for the visual detection of copper ions in confined space.A fluorescence microparticle,named AuNCs/ZIF-8,was synthesized by coating gold nanoclusters (AuNCs) onto the outer surface of zeo-litic imidazolate framework-8 (ZIF-8).The morphology and solid-state fluorescence property of AuNCs/ZIF-8 were characterized by scanning electron microscopy and fluorescence technique.The AuNCs/ZIF-8 exhibits turn-off responses to copper ions via fluores-cence quenching in the range of 2-15 μmol·L-1 with a detection limit of 0.9 μmol·L-1.More importantly,the distribution of AuNCs on single ZIF-8 crystal and the fluorescence quenching dynamics on single AuNCs/ZIF-8 were visualized by 3D-reconstructed fluorescence imaging.Different distribution of AuNCs on the different surfaces of single ZIF-8 crystal and similar fluorescence quenching dynamics on the different surfaces of single AuNCs/ZIF-8 were obtained.These results offer insights into the nature of the fluorescence active sites and the fluorescence quenching dynamics on a single fluorescence particle,which also opens up new opportunities for in situ target biomolecule analysis in confined space.