Nanoconfinement-Enhanced Electrochemiluminescence for in Situ Imaging of Single Biomolecules

Abstract

Direct imaging of electrochemical reactions at the single-molecule level is of potential interest in materials, diagnostic, and catalysis applications. Electrochemiluminescence (ECL) offers the opportunity to convert redox events into photons. However, it is challenging to capture single photons emitted from a single-molecule ECL reaction at a specific location, thus limiting high-quality imaging applications. We developed the nanoreactors based on Ru(bpy)3 2+-doped nanoporous zeolite nanoparticles (Ru@zeolite) for direct visualization of nanoconfinement-enhanced ECL reactions. Each nanoreactor not only acts as a matrix to host Ru(bpy)3 2+ molecules but also provides a nanoconfined environment for the collision reactions of Ru(bpy)3 2+ and co-reactant radicals to realize efficient in situ ECL reactions. The nanoscale confinement resulted in enhanced ECL. Using such nanoreactors as ECL probes, a dual-signal sensing protocol for visual tracking of a single biomolecule was performed. High-resolution imaging of single membrane proteins on heterogeneous cells was effectively addressed with near-zero backgrounds. This could provide a more sensitive tool for imaging individual biomolecules and significantly advance ECL imaging in biological applications.

Enhanced electrochemiluminescence imaging of single cell membrane proteins based on Co3O4 nanozyme catalysis

“…3). Compared with the previous ECL imaging analysis, 12,31,32 the presence of the Co 3 O 4 nanozyme can shorten the exposure time obviously, indicating that the catalytic activity of the Co 3 O 4 nanozyme can significantly enhance the ECL luminescence of the L012-H 2 O 2 system, endowing it with higher temporal resolution. In addition, the stability of ECL luminescence using the Co 3 O 4 nanozyme as a catalyst was also investigated.…”

“…This new imaging method can not only achieve high-throughput and visualization of biomolecules, 7 but also be applied to the research of spatiotemporal resolution imaging of single entities such as particles, cells and bacteria. [8][9][10][11][12] It can provide more spatial detail information, such as identification of cellular contents and structures. Small molecules in cells or released from cells, (sub-)cellular structures including cell membranes, 13,14 proteins, 10,15 mitochondria 16 and intracellular hierarchical structures such as the nucleolus, nucleus and endoplasmic reticulum 17 have been visualized by ECL imaging.…”

Electrochemiluminescence imaging of a membrane carcinoembryonic antigen at single tissue sections

“…As a result, this new imaging method has been successfully applied to the visualization of varied biomolecules at the single-cell level, [8][9][10][11] and recently developed to high-resolution imaging of single biomolecules. 12,13 In addition, the generation of ECL through the electrochemical reaction of luminophores occurs within a few microns from the electrode surface, showing a characteristic of near-field visualization. 14 The surface confinement of the ECL process should be able to further avoid the background influence from tissue sections of a certain thickness.…”

Identification and Quantification of 5-Methylcytosine and 5-Hydroxymethylcytosine on Random DNA Sequences by a Nanoconfined Electrochemiluminescence Platform

“…Our previous work has highlighted the fact that the ECL intensity of Ru­(bpy) 3 2+ could be dramatically enhanced by the covalent organic framework (COF) modified electrode. This might be ascribed to the nanoconfinement-enhanced ECL effect, which would increase the concentration and prolong the lifetime of radicals in electrochemical reactions, further increasing the productivity of excited states. − Inspired by these findings, a silicon nanonetwork would give a fresh impetus to improve the ECL intensity due to its rigid nanospace, high porosity, and a large number of exposed active groups. Thus, the nanoconfinement-enhanced ECL strategy based on a silicon network was proposed in this work by encapsulating CPDs with a silicon dioxide (SiO 2 ) nanonetwork (CPDs@SiO 2 ) through a sol–gel method to obtain a strong and stable ECL signal.…”