Dynamically imaging stochastic collision electrochemistry of single nanoparticles by electrochemiluminescence microscopy enables visualization of diverse collision behaviours.

A bio‐coreactant‐enhanced electrochemiluminescence (ECL) microscopy realizes the ECL imaging of intracellular structure and dynamic transport. This microscopy uses Ru(bpy)32+ as the electrochemical molecular antenna connecting extracellular and intracellular environments, and uses intracellular biomolecules as the coreactants of ECL reactions via a “catalytic route”. Accordingly, intracellular structures are identified without using multiple labels, and autophagy involving DNA oxidative damage is detected using nuclear ECL signals. A time‐resolved image sequence discloses the universal edge effect of cellular electroporation due to the influence of the geometric properties of cell membranes on the induced transmembrane voltage. The dynamic transport of Ru(bpy)33+ in the different cellular compartments unveils the heterogeneous intracellular diffusivity correlating with the actin cytoskeleton. In addition to single‐cell studies, the bio‐coreactant‐enhanced ECL microscopy is used to image a slice of a mouse liver and a colony of Shewanella oneidensis MR‐1.

This article describes a multimodified core-shell gold@silver nanoprobe for real-time monitoring the entire autophagy process at single-cell level. Autophagy is vital for understanding the mechanisms of human pathologies, developing novel drugs, and exploring approaches for autophagy controlling. A major challenge for autophagy study lies in real-time monitoring. One solution might come from real-time detection of in situ superoxide radicals (O2(•-)), because it is the main regulator of autophagy. In this work, our proposed nanoprobes were etched by O2(•-) and gave a notable wavelength change in the plasmon resonance scattering spectra. Both the experimental and simulated results suggested the wavelength change rate correlated well with O2(•-) level. This response enabled its application in real-time in situ quantification of O2(•-) during autophagy course. More importantly, with the introduction of "relay probe" operation, two types of O2(•-)-regulating autophagy processes were successfully traced from the beginning to the end, and the possible mechanism was also proposed.

Measuring local heat generation and dissipation in nanomaterials is critical for understanding the basic properties and developing applications of nanomaterials, including photothermal therapy and joule heating of nanoelectronics. Several technologies have been developed to probe local temperature distributions in nanomaterials, but a sensitive thermal imaging technology with high temporal and spatial resolution is still lacking. Here, we describe plasmonic thermal microscopy (PTM) to image local heat generation and diffusion from nanostructures in biologically relevant aqueous solutions. We demonstrate that PTM can detect local temperature change as small as 6 mK with temporal resolution of 10 μs and spatial resolution of submicrons (diffraction limit). With PTM, we have successfully imaged photothermal generation from single nanoparticles and graphene pieces, studied spatiotemporal distribution of temperature surrounding a heated nanoparticle, and observed heating at defect sites in graphene. We further show that the PTM images are in quantitative agreement with theoretical simulations based on heat transport theories.

Lead halide perovskite quantum dots (QDs) are promising electrochemiluminescence (ECL) nanoemitters due to their fascinating photophysical properties. However, due to their poor structural stability against the external environment, the trade-off between their colloidal stability and carrier injection/transport efficiency is a major challenge in the advancement of perovskite-based ECL technology. In this work, intense and stable ECL from CsPbBr 3 (CPB) QDs is achieved by simultaneously encapsulating CPB QDs and coreactant (CoR) into in situ generated SiO 2 matrix via hydrolysis of tetramethyl orthosilicate. The well-designed architecture of the as-obtained CPB-CoR@SiO 2 nanocomposites (NCs) guarantees not only greatly improved stability thanks to the peripheral SiO 2 protecting matrix, but also efficient self-enhanced ECL between CPB and the intra-coreactants. Consequently, by elaborately selecting the CoR molecules with different tertiary/secondary amines and functional groups, multifold higher (up to 10.2 times) ECL efficiencies are obtained for the CPB-CoR@SiO 2 NCs alone in reference to the standard Ru(bpy) 3 2+ /tri-n-propylamine system. This work provides an efficient design strategy for obtaining stable and highly efficient ECL from perovskite QDs, and offers a new perspective for the development and application of perovskite-based ECL system.

Single-cell imaging is essential for elucidating the biological mechanism of cell function because it accurately reveals the heterogeneity among cells. The electrochemiluminescence (ECL) microscopy technique has been considered a powerful tool to study cells because of its high throughput and zero cellular background light. However, since cells are immobilized on the electrode surface, the steric hindrance and the insulation from the cells make it difficult to obtain a luminous cell ECL image. To solve this problem, direct ECL imaging of a single cell was investigated and achieved on chitosan and nano-TiO modified fluoride-doped tin oxide conductive glass (FTO/TiO/CS). The permeable chitosan film is not only favorable for cell immobilization but also increases the space between the bottom of cells and the electrode; thus, more ECL reagent can exist below the cells compared with the cells on a bare electrode, which guarantees the high sensitivity of quantitative analysis. The modification of nano-TiO strengthens the ECL visual signal in luminol solution and effectively improves the signal-to-noise ratio. The light intensity is correlated with the HO concentration on FTO/TiO/CS, which can be applied to analyze the HO released from cells at the single-cell level. As far as we know, this is the first work to achieve cell ECL imaging without the steric hindrance effect of the cell, and it expands the applications of a modified electrode in visualization study.

Monitoring and characterization methods that provide performance tracking of hydrogen evolution reaction (HER) at the single-nanoparticle level can greatly advance our understanding of catalysts’ structure and activity relationships. Electrochemiluminescence (ECL) microscopy is implemented for the first time to identify HER activities of single nanocatalysts and to provide a direction for further optimization. Here, we develop a novel ECL blinking technique at the single-nanoparticle level to directly monitor H2 nanobubbles generated from hollow carbon nitride nanospheres (HCNSs). The ECL ON and OFF mechanisms are identified being closely related to the generation, growth, and collapse of H2 nanobubbles. The power-law distributed durations of ON and OFF states demonstrate multiple catalytic sites with stochastic activities on a single HCNS. The power-law coefficients of ECL blinking increase with improved HER activities from modified HCNSs with other active HER catalysts. Besides, ECL blinking phenomenon provides an explanation for the low cathodic ECL efficiency of semiconductor nanomaterials.

Double perovskites Cs2AgSbCl6 have been synthesized via the solution state for applications as a promising photovoltaic absorber. Considering TiO2 as an electron transport layer (ETL), Cs2AgSbCl6/TiO2 heterojunction nanoparticles have also been prepared by the hydrothermal process to study the interface effect. Experimental measurements show that Cs2AgSbCl6 has a cubic structure with the lattice constant of 10.699 Å. The absorption peaks in the optical spectrum of the Ag and Sb-based double perovskites agree well with our density functional theory calculations. The Cs2AgSbCl6/TiO2 heterostructure exhibits enhanced optical absorption in the visible-light region compared to that of Cs2AgSbCl6, which is caused by the formation of the interface states and the decreased bandgap, thus facilitating the photo-induced optical transition in the visible-light region. From the charge transfer analysis of two interfaces (Ag2Sb2Cl8/TiO2 and Cs4Cl4/TiO2 interfaces), we find that the efficient separation of photo-induced carriers can be achieved at the Cs4Cl4/TiO2 interface, with electron flowing from the double perovskite layer to the TiO2 ETL, which is beneficial for improving the power conversion efficiency of solar cells. The combined study of theory and experiments indicates that the double perovskites Cs2AgSbCl6 would be a promising light-absorbing material in contact with TiO2 for the lead-free perovskite-based solar cell devices.