Cheng Ma

Electrocatalytic nitrate reduction (NO₃RR) provides a sustainable approach for removing nitrate pollutants and producing valuable nitrogen chemicals. However, understanding catalytic behavior under realistic dilute conditions remains challenging, as conventional electrochemical measurements rely on ensemble-averaged signals that obscure dynamic interfacial processes at individual particles. Here we show an operando electrochemiluminescence (ECL) microscopy strategy that visualizes and evaluates apparent NO₃RR kinetics at the single-particle level. Using Cu(111) nanosheets as a model catalyst, we convert reaction-induced optical responses into spatially resolved descriptors of nitrate adsorption and intermediate evolution. The time-dependent ECL response reveals the generation and diffusion of nitrite, a key intermediate in nitrate reduction. These descriptors provide apparent kinetic mapping, uncovering substantial kinetic heterogeneity of individual particles. Correlative imaging of intermediate diffusion demonstrates that interparticle coupling influences apparent catalytic performance by modulating intermediate accumulation and interfacial mass transport under dilute nitrate conditions. This approach provides an operando optical microscopy platform for visualizing dynamic catalytic interfaces and linking interfacial processes with apparent catalytic performance.

Understanding how applied voltage regulates metabolism in microbial electrochemical systems is challenging due to the lack of adequate electrophysiological tools for microorganisms. Here, we present an imaging platform based on electrochemiluminescence (ECL) that allows real-time, femtocoulomb-scale quantification of surface charge in single bacterial cells. The method exploits the electrostatic enrichment of cationic luminophores at bacterial membranes to amplify ECL signals, thereby linking surface charge dynamics to intracellular electron metabolism and interfacial electron flow. Using Shewanella oneidensis MR-1 as a model, we show voltage-activated metabolic enhancement mediated by outer-membrane cytochromes. By modulating direct and indirect electron-transfer pathways, we reveal that cytochrome-dependent direct electron transfer initiates activation, while mediator-enabled indirect electron transfer prevents charge saturation and sustains elevated metabolic turnover. Furthermore, dual-parameter screening enables identification of bacterial subpopulations with high metabolic activity and efficient electron transfer capability. Thus, our work provides a framework for microbial electrophysiology at the single-cell level and opens potential avenues for engineering high-performance electroactive strains for bio-electrochemical applications.

Accurately assessing how individual cells respond to anticancer agents remains challenging because most assays provide bulk or binary readouts and cannot translate single-cell imaging into scalable, mechanism-relevant quantification. Here, we develop a nuclear DNA-gated electrochemiluminescence (ECL) microscopy assay in which genomic DNA acts as an intrinsic coreactant for Ru(bpy)₃²⁺, converting apoptosis-associated chromatin condensation and fragmentation into spatially resolved decreases in nuclear ECL intensity. The resulting signal provides a dose- and time-dependent measure of the apoptotic progression. For drug-treated cells, a deep learning model trained on ECL images enables high-throughput classification of apoptotic and nonapoptotic cells, allowing quantitative apoptosis profiling across large datasets. Using this framework, we compare the apoptotic potency of three natural anticancer compounds and reveal distinct spatial damage signatures for two photosensitizers, reflecting their different ROS-mediated pathways. This integrated approach offers a quantitative and scalable strategy for single-cell apoptosis profiling.

This study constructs the first composite system integrating PMo ₁₀ V ₂ polyoxometalate nanoclusters with Co-based nanomaterials, which exhibits outstanding performance in both electrocatalytic nitrite reduction and Zn–NO ₂ ⁻ batteries.

In situ photoluminescence electrochemical microscopy achieved micrometre-scale heterogeneity probing of electrode surfaces by synchronously acquiring photoluminescence signals and electrical signals on electrode surfaces.

Ion channels as transmembrane proteins provide an important transport pathway for specific ions through cell membranes, which are crucial to studies involving the pathophysiology of the nervous system. However, the switch between different conformational states (i.e., open versus closed) of a channel is difficult to be in situ identified with a high throughput. Here, we proposed ionic tunable electrochemiluminescence (ECL) imaging to study ion channels in a simple manner. The ionic influx via ion channels across the cell membrane determines the amount of intracellular ECL luminophores, which is displayed by two ECL patterns (negative versus positive) in cellular regions. Owing to the variable permeable selectivity of the plasma membrane to different ions, the dynamic ECL pattern transformation reflects the penetration competition of different cations in extracellular circumstances. The universality of ECL pattern transformation is validated with respect to different kinds of cells. More importantly, the cellular ECL pattern reflects the specific interaction between the ion channel and its modulators including inhibitors and agonists, providing a tool to screen potential drugs that target ion channels.

In situ disclosure about the complex four‐electron transfer of anodic oxygen evolution reaction (OER) is crucial to further optimization of electrocatalysts. However, tracing the formation and evolution of unstable intermediates remains challenging. Here, electrochemiluminescence (ECL) analysis and imaging technique are developed to in situ monitor the important intermediate hydrogen peroxide intermediate (OOH*) on transition‐metal‐based 7,7,8,8‐tetracyanoquinodimethane (TM─TCNQ) metal–organic framework materials as OER catalysts. Thanks to the highly selective ECL probe L‐012 to OOH*, the ECL signal evolution (e.g., onset ECL potential and maximal ECL intensity) is bridged with the generation and accumulation of OOH*, allowing for convenient and quick judgment to the rate‐determining step of OER. Due to the spatial and temporal resolution of ECL microscopy, it is found that the phase I of Cu─TCNQ shows better catalytic activity. The COMSOL simulation also shows the heterogeneous current distribution during the OER reaction, in agreement with ECL imaging results. Finally, the ECL approach enables to compare the OER performance of three TM─TCNQ, well explaining the free energy profiles for different reaction intermediates. Therefore, the proposed ECL analysis and microscopy provide an alternative way to understand the detailed elemental steps in OER, thus further indicating the direction for high‐performance catalysts.

Cellular bottom structure plays a vital role in cell mobility, but its narrow space makes it difficult to study. Currently, it remains challenging to panoramically map the cellular bottom topography variations due to the potential cellular damage and off-target effects of luminophores when using current ultra-high-resolution optical microscopy. Here, we present charge-lock spatiotemporal transformation electrochemiluminescence (CL-STTECL) microscopy. The ECL is "locked" by the charge exclusion between cationic luminophores and the proton film, while amine co-reactants simultaneously "unlock" this process. Consequently, the uneven distribution of luminophores at the cellular base triggers a gap distance-dependent ECL emission trajectory, allowing the identification of cell-matrix gap distance heterogeneity at an axial spatial resolution of ∼10 nm. Using CL-STTECL microscopy, we demonstrated changes in cellular bottom topography in response to various external stimulations and uncovered heterogeneity in panoramic features between normal tissue cells and metastatic cancer cells, offering a novel approach for early cancer screening.

Electrochemical imaging enables an in‐depth analysis of the interface heterogeneity and reaction kinetics of single entities. However, electrode passivation during electrochemical reactions decreases the active sites and harms the long‐term stability. Here, we introduce a method using laser‐induced photothermal effects to restore the electrochemical activity, which is particularly displayed as enhanced micrometric patterns in electrochemiluminescence (ECL) microscopy. By co‐localization characterization and X‐ray photoelectron spectroscopy (XPS), the mechanism of active site regeneration is validated as the removal of the oxide film for restoring the local surface ECL reactivity under laser irradiation. The surface‐confined and voltage‐dependent features of ECL allows for easy pattern erasure and rewriting, and it shows good reversibility and anti‐counterfeiting potential. This approach overcomes the passivation processes, evidently improves the image quality of single biological entities including Shewanella bacteria and cells, and makes the subtle contour structures more distinct. The renewable electrode interface also enhances the ECL signal of model bead‐based bioassays. This approach not only showcases precise control in fabricating micron patterns but also holds promise for enhancing the sensitivity in electrochemical immunoassays and bioimaging.

Electrochemical imaging enables an in‐depth analysis of the interface heterogeneity and reaction kinetics of single entities. However, electrode passivation during electrochemical reactions decreases the active sites and harms the long‐term stability. Here, we introduce a method using laser‐induced photothermal effects to restore the electrochemical activity, which is particularly displayed as enhanced micrometric patterns in electrochemiluminescence (ECL) microscopy. By co‐localization characterization and X‐ray photoelectron spectroscopy (XPS), the mechanism of active site regeneration is validated as the removal of the oxide film for restoring the local surface ECL reactivity under laser irradiation. The surface‐confined and voltage‐dependent features of ECL allows for easy pattern erasure and rewriting, and it shows good reversibility and anti‐counterfeiting potential. This approach overcomes the passivation processes, evidently improves the image quality of single biological entities including Shewanella bacteria and cells, and makes the subtle contour structures more distinct. The renewable electrode interface also enhances the ECL signal of model bead‐based bioassays. This approach not only showcases precise control in fabricating micron patterns but also holds promise for enhancing the sensitivity in electrochemical immunoassays and bioimaging.