High Electrochemiluminescence from Ru(bpy)32+ Embedded Metal-Organic Frameworks to Visualize Single Molecule Movement at the Cellular Membrane

Direct imaging of single-molecule and its movement is of fundamental importance in biology, but challenging. Herein, aided by the nanoconfinement effect and resultant high reaction activity within metal-organic frameworks (MOFs), the designed Ru(bpy)(3)(2+) embedded MOF complex (RuMOFs) exhibits bright electrochemiluminescence (ECL) emission permitting high-quality imaging of ECL events at single molecule level. By labeling individual proteins of living cells with single RuMOFs, the distribution of membrane tyrosine-protein-kinase-like7 (PTK7) proteins at low-expressing cells is imaged via ECL. More importantly, the efficient capture of ECL photons generated inside the MOFs results in a stable ECL emission up to 1 h, allowing the in operando visualization of protein movements at the cellular membrane. As compared with the fluorescence observation, near-zero ECL background surrounding the target protein with the ECL emitter gives a better contrast for the dynamic imaging of discrete protein movement. This achievement of single molecule ECL dynamic imaging using RuMOFs will provide a more effective nanoemitter to observe the distribution and motion of individual proteins at living cells.

Automated summary

In this study, a designed Ru(bpy)(3)(2+) embedded MOF complex (RuMOFs) is used for high-quality imaging of electrochemiluminescence (ECL) events at a single molecule level. The efficient capture of ECL photons generated inside the MOFs allows for stable ECL emission for up to 1 hour, enabling the visualization of protein movements at the cellular membrane. Compared to fluorescence observation, the near-zero ECL background provides better contrast for dynamic imaging of discrete protein movement.