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Effective bimetallic nanoelectrocatalysis demands precise control of composition, structure, and understanding catalytic mechanisms. To address these challenges, we employ a two-in-one approach, integrating online synthesis with real-time imaging of bimetallic Au@Metal core-shell nanoparticles (Au@M NPs) via electrochemiluminescence microscopy (ECLM). Within 120 s, online electrodeposition and in situ catalytic activity screening alternate. ECLM captures transient faradaic processes during potential switches, visualizes electrochemical processes in real-time, and tracks catalytic activity dynamics at the single-particle level. Analysis using ECL photon flux density eliminates size effects and yields quantitative electrocatalytic activity results. Notably, a nonlinear activity trend corresponding to the shell metal to Au surface atomic ratio is discerned, quantifying the optimal surface component ratio of Au@M NPs. This approach offers a comprehensive understanding of catalytic behavior during the deposition process with high spatiotemporal resolution, which is crucial for tailoring efficient bimetallic nanocatalysts for diverse applications.
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In this study, we proposed a novel imaging technique, photoinduced electrogenerated chemiluminescence microscopy (PECLM), to monitor redox reactions driven by hot carriers on single gold nanoparticles (AuNPs) on TiO2. Under laser irradiation, plasmon-generated hot carriers were separated by an electric field, leaving hot holes on the surface of AuNPs to drive ECL reactions. PECL intensity was highly sensitive to the number of hot carriers. Through quantitative image analysis, we found that PECL density on individual AuNPs decreased significantly with an increase in particle diameter, indicating that particle size has a significant impact on photoelectrochemical conversion efficiency. For the first time, we verified the feasibility of PECLM in mapping the catalytic activity of single photocatalysts. PECLM opens a new prospect for the in situ imaging of photocatalysis in a high-throughput way, which not only facilitates the optimization of plasmonic photocatalysts but also contributes to the dynamic study of photocatalytic processes on micro/nanointerfaces.
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Single-atom catalysts (SACs), distinguished by their maximum atom efficiency and precise control over the coordination and electronic properties of individual atoms, show great promise in electrocatalysis. Gaining a comprehensive understanding of the electrochemical performance of SACs requires the screening of electron transfer process at micro/nano scale. This research pioneers the use of electrogenerated chemiluminescence microscopy (ECLM) to observe the electrocatalytic reactions at individual SACs. It boasts sensitivity at the single photon level and temporal resolution down to 100â ms, enabling real-time capture of the electrochemical behavior of individual SACs during potential sweeping. Leveraging the direct correlation between ECL emission and heterogeneous electron transfer processes, we introduced photon flux density for quantitative analysis, unveiling the electrocatalytic efficiency of individual SACs. This approach systematically reveals the relationship between SACs based on different metal atoms and their peroxidase (POD)-like activity. The outcomes contribute to a fundamental understanding of SACs and pave the way for designing SACs with diverse technological and industrial applications.
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Single-atom catalysts (SACs), a novel kind of electrocatalysts with full metal utilization, have been developed as unique signal amplifiers in several sensing platforms. Herein, based on theoretical prediction of the oxygen reduction reaction (ORR) mechanism on different atom sites, we constructed dual-atomic-site catalysts (DACs), Fe/Mn-N-C, to catalyze luminol-dissolved oxygen electrochemiluminescence (ECL). Computational simulation indicated that the weak adsorption of OH* on a single Fe site was overcome by introducing Mn as the secondary metallic active site, resulting in a synergic dual-site cascade mechanism. The superior catalytic activity of Fe/Mn-N-C DACs for the ORR was proven by the highly efficient cathodic luminol ECL, surpassing the performance of single-site catalysts (SACs), Fe-N-C and Mn-N-C. Furthermore, the ECL system, enhanced by a cascade reaction, exhibited remarkable sensitivity to ascorbic acid, with a detection limit of 0.02 nM. This research opens up opportunities for enhancing both the ECL efficiency and sensing performance by employing a rational atomic-scale design for DACs.
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We report a photodynamic therapy driven by electrochemiluminescence (ECL). The luminescence generated by Ru(bpy)32+ and co-reactant tripropylamine (TPA) pair acts as both optical readout for ECL imaging, and light source for the excitation of photosensitizer to produce reactive oxygen species (ROS) in photodynamic therapy (PDT) system. The ECL-driven PDT (ECL-PDT) relies on the effective energy transfer from ECL emission to photosensitizer chlorin e6 (Ce6), which sensitizes the surrounding O2 into ROS. The dynamic process of gradual morphological changes, the variation of cell-matrix adhesions, as well as the increase of cell membrane permeability in the process of ECL-PDT were monitored under ECL microscopy (ECLM) with good spatiotemporal resolution. Combining real-time imaging with ECL-PDT, this new strategy provides not only new insights into dynamic cellular processes, but also promising potential of ECL in clinical applications.
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Fotoquimioterapia , Transferência de Energia , Luminescência , Fármacos Fotossensibilizantes/farmacologiaRESUMO
Electrogenerated chemiluminescence microscopy (ECLM) provides a real-time imaging approach to visualize the surface-dependent catalytic activity of nanocatalysts, which helps to rationalize the design of catalysts. In this study, we first propose super-resolution ECLM that could measure the facet- and site-specific activities of a single nanoparticle with nanometer resolution. The stochastic nature of the ECL emission makes the generation of photons obey Poisson statistics, which fits the requirement of super-resolution radial fluctuation (SRRF). By processing an SRRF algorithm, the spatial resolution of ECL images achieved ca. 100 nm, providing more abundant details on electrocatalytic reactivities at the subparticle level. Beyond conventional wide-field ECL imaging, super-resolution ECLM provided the spatial distribution of catalytic activities at a Au nanorod and nanoplate with scales of a few hundred nanometers. It helped uncover the facet- and defect-dependent surface activity, as well as the dynamic fluctuation of reactivity patterns on single nanoparticles. The super-resolution ECLM provides high spatiotemporal resolution, which shows great potential in the field of catalysis, biological imaging, and single-entity analysis.
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In clinical diagnosis, the level of biological enzymes in serum has been generally regarded as markers of human diseases. In this work, a kind of simple and sensitive plasmonic probe (indicated as Au@FeOOH) has been synthesized with the guidance of plasmonic imaging and subsequently developed for the alkaline phosphatase (ALP) level detection under dark-field microscopy (DFM). As a kind of hydrolysis enzyme, ALP can promote the hydrolysis of l-ascorbic acid 2-phosphate to ascorbic acid (AA). AA further acts as a strong reduction reagent for the decomposition of the FeOOH shell, which results in a blue shift of localized surface plasmon resonance spectra and an obvious color change under DFM. RGB analyses show that using a ΔR/G value instead of scattering wavelength or R/G value as the analytical signal, the deviation attributed to the size distribution of the initial Au NPs is greatly suppressed, and a linear range from 0.2 to 6.0 U/L (R2 = 0.99) and a limit of detection of 0.06 U/L are acquired with various concentrations of ALP during the detection. Besides, this approach exhibits excellent selectivity in complex biological serum samples, which is expected to be applied for the early diagnosis of clinical diseases by monitoring various biomarkers in the future.
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Fosfatase Alcalina , Nanopartículas Metálicas , Ácido Ascórbico , Bioensaio , Humanos , Limite de Detecção , Microscopia , Ressonância de Plasmônio de SuperfícieRESUMO
Single particle plasmon scattering can provide real-time imaging information on the synthesis of nanomaterials. Here, an electrochemical deposition strategy is reported to synthesize plasmonic Au@Metal core-shell nanoparticles (Au@M NPs), which exhibit localized surface plasmon resonance (LSPR) properties. Because of the excellent catalytic activity of the methanol oxidation reaction (MOR), Pt, Pd, and Rh were reduced on the surface of Au NPs to form monometallic and bimetallic shells. Under dark field microscopy (DFM), the scattering changes could be utilized to track the surface nucleation and bulk deposition process. The synthesized Au@M NPs, which combined the plasmonic and electrocatalytic features, showed greatly enhanced activity for MOR. Under LSPR excitation, the electroxidation process toward MOR was accelerated and increased approximately linearly with increased illumination intensity, which could be mostly attributed to the generation of energetic charge carriers. This strategy of real-time plasmonic tracking electrochemical deposition at the single particle level is facile and universal, which could be extended to the precise synthesis of other plasmonic core-shell nanomaterials and the investigation of the pathway of plasmon accelerated chemical conversion.
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Here, we proposed a novel local surface plasmon resonance (LSPR) enhanced ECL strategy based on the metallic inverse opals and Ru(bpy)32+-doped silica nanoparticles (RuSi NPs). Gold inverse opals (GIOs), as a plasmonic array, could interact with the ECL of RuSi NPs and excite the electromagnetic (EM) field at the gold surface. The triggered EM field could enhance the ECL emission of RuSi NPs. We compared the electrochemical and ECL performances of RuSi NPs modified on the gold electrodes with different surface morphologies and found that the ECL emission of RuSi NPs patterned at the inner surface of GIOs exhibited the highest intensity. The finite-difference time-domain (FDTD) simulations indicated that the EM field was related to the surface morphology of the metallic nanostructure, and the highest EM field was observed at the inner surface of the GIOs. Because of the superior ECL performances, the inner surfaces of GIOs were developed for nucleic acid detection with a detection limit of 3.3 fM (S/N = 3), which shows great promise for bioanalysis.
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Técnicas Eletroquímicas/métodos , Ouro/química , Substâncias Luminescentes/química , Medições Luminescentes/métodos , Nanopartículas Metálicas/química , MicroRNAs/análise , Técnicas Biossensoriais/métodos , DNA/química , DNA/genética , Técnicas Eletroquímicas/instrumentação , Eletrodos , Limite de Detecção , MicroRNAs/genética , Hibridização de Ácido Nucleico , Compostos Organometálicos/química , Dióxido de Silício/química , Estreptavidina/química , Ressonância de Plasmônio de SuperfícieRESUMO
This paper develops an efficient electrochemiluminescence (ECL) enhancement strategy on closed bipolar electrode for the detection of prostate specific antigen (PSA). We first synthesized a cyclometalated iridium(III) complex (pq)2Irbza with high ECL efficiency and used as ECL emitter in the anodic cell of BPE. While we introduced a Pt-tipped Au NRs and constructed a sandwich immune structure at the cathodic pole of BPE. Combined the signal amplification strategies of enzyme catalysis and the synergistic catalytic effect of bimetallic structure for the reduction of H2O2, the attached Pt-tipped Au NRs-GOx-Ab2 nanocomplex as both recognition probes and signal amplification units could mediate the ECL signals of (pq)2Irbza/tripropylamine (TPrA) on the anodes of BPE through faradaic reaction due to the charge neutrality of BPE. Therefore, a highly sensitive BPE-ECL sensor for detection of PSA with a detection limit of 0.72 pg/mL and a linear range from 1.0 pg/mL to 10 ng/mL was obtained. This work is expected to broaden the application of iridium complex and bimetallic nanocatalyst in biological detection and could be utilized to detect many other biological molecules.
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Eletroquímica/instrumentação , Medições Luminescentes , Antígeno Prostático Específico/análise , Eletrodos , Irídio/química , Compostos Organometálicos/química , Propilaminas/química , Antígeno Prostático Específico/químicaRESUMO
Innovative techniques to measure microRNA (miRNA) in vivo could greatly improve the fundamental understanding of complex cellular processes. Herein, we report a novel method for real-time, quantitative miRNA detection inside living cells based on core-satellite plasmon rulers (PRs). This approach allows for the statistical analysis of single hybridization event caused by target miRNA. We investigated hundreds of satellite leaving events and found that the distribution of the time range for one strand displacement event is miRNA concentration-dependent, which obeyed Poisson statistics. Probing several such PRs under dark-field microscopy would provide precise determination of miRNA in vitro and in living cells, without photobleaching or blinking of the fluorophores. We believe the simple and practical approach on the basis of dynamic PRs with single-molecule sensitivity combined with statistical analysis hold promising potential to visualize native nucleic acids with short sequence and low-abundance.
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DNA Complementar/metabolismo , DNA de Cadeia Simples/metabolismo , MicroRNAs/análise , Microscopia/métodos , Linhagem Celular , DNA Complementar/química , DNA de Cadeia Simples/química , Ouro/química , Células HeLa , Humanos , Nanopartículas Metálicas/química , MicroRNAs/metabolismo , Hibridização de Ácido Nucleico , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Ionic current rectification (ICR) based nanopipettes allow accurate monitoring of cellular behavior in single living cells. Herein, we proposed a 30â nm nanopipette functionalized with G-quadruplex DNAzyme as an efficient biomimetic recognizer for ROS generation at subcellular level via the changes of current-voltage relationship. Taking advantages of the ultra-small tip, the nanopipette could penetrate into a single living cell repeatedly or keep measuring for a long time without compromising the cellular functions. Coupled with precision nanopositioning system, generation of ROS in mitochondria in response to cell inflammation was determined with high spatial resolution. Meanwhile, the changes of aerobic metabolism in different cell lines under drug-induced oxidative stress were monitored continuously. We believe that the ICR-nanopipette could be developed as a powerful approach for the study of cellular activities via electrochemical imaging in living cells.
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Nanotecnologia/métodos , Linhagem Celular , DNA Catalítico/química , Quadruplex G , Humanos , Peróxido de Hidrogênio/química , Íons/química , Nanotecnologia/instrumentação , Oxirredução , Espécies Reativas de Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo , Análise de Célula ÚnicaRESUMO
We report a multicolor ECL device based on closed bipolar electrode (BPE) for the visualized sensing of prostate-specific antigen (PSA) in human blood serum. As the emission color of concomitant electrochemiluminophores is potential resolved, similar to a three-electrode system, selective excitation of ECL could be achieved by tuning the interfacial potential at the poles of BPE. Via modulating the resistance of BPE, multicolor ECL emission of [Ru(bpy)3]2+ and [Ir(ppy)3] mixture using tripropylamine (TPrA) as the co-reactant was observed at the anode and the principle was elaborated. The concept was utilized to the quantification of clinical biomarkers with the color variation. A PSA concentration dependent silver bridge was constructed in the gap of the BPEs as an electric conductivity modulator. On the basis of a multicolor BPE-ECL device, the cutoff values (4.0 and 10.0 ng/mL) of human PSA could be recognized with naked eyes by the green-yellow-red ECL emission changing. As the first multicolor ECL device in biological analysis, BPE may raise the application of potential-resolved ECL to a new level.
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Técnicas Biossensoriais/métodos , Medições Luminescentes/métodos , Antígeno Prostático Específico/sangue , Complexos de Coordenação/química , Técnicas Eletroquímicas , Eletrodos , Humanos , Compostos Organometálicos/química , Propilaminas/químicaRESUMO
This study explores plasmon-induced electrochemical reactions on single nanoparticles using electrogenerated chemiluminescence microscopy (ECLM). Under laser irradiation, real-time screening showed lower plasmon-induced reaction efficiency for bimetallic Au@Pt nanoparticles compared to monometallic Au nanoparticles. ECLM offers a high-throughput imaging and precise quantitative approach for analyzing photo-electrochemical conversion at single nanoparticle level, valuable for both theoretical exploration and optimization of plasmonic nanocatalysts.
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BACKGROUND: The advancement of highly sensitive electrochemiluminescence (ECL) biosensors has garnered escalating interest over time. Owing to the distinctive physicochemical attributes, the signal amplification strategy facilitated by functional nanomaterials has achieved notable milestones. Single-atom catalysts (SACs), featuring atomically dispersed metal active sites, have garnered significant attention. SACs offer unprecedented control over active sites and surface structures at the atomic level. However, to fully harness their potential, ongoing efforts focus on strategies to enhance the catalytic performance of SACs, profoundly influencing both the sensitivity and selectivity of SACs-based sensing platforms. RESULTS: In this study, we focused on the synthesis and application of Fe-Co-PNC dual-atom catalysts (DACs) with the incorporation of phosphorus, aiming to enhance catalytic efficiency, particularly in the context of the oxygen reduction reaction (ORR) correlated cathodic luminol ECL. The synergistic effects arising from the combination of Fe and Co in DACs were explored by ECL emission. Comparative studies with Fe-PNC SACs highlighted the superior catalytic performance of Fe-Co-PNC DACs. The ECL sensing platform exhibited excellent sensitivity, which provided a fast detection of Trolox with a wide linear range (0.1 µM-1.0 mM) and a low detection limit (LOD) of 0.03 µM. The platform demonstrated remarkable reproducibility and long-term stability, showcasing its potential for practical biosensing applications. SIGNIFICANCE: This study introduced the novel concept of Fe-Co-PNC DACs. The demonstrated synergistic effects and enhanced catalytic efficiency of DACs offer new avenues for the rational design of advanced catalysts. The successful application in the sensitive detection of Trolox emphasizes their potential significance in biosensing. It not only expands our understanding of SACs but also opens doors for the development of efficient and stable catalysts with broader applications.
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The epidemiological features of 298 imported malaria cases during 2008-2012 in Guangzhou were analyzed. Among the cases, 169 (56.7%) were falciparum malaria, 106 (35.6%) were vivax malaria, and 23 (7.7%) were unidentified. The proportion of falciparum malaria cases was raising gradually in the last 5 years. Most of the cases were infected in malaria endemic regions of Africa and South-East Asia. Among them, 160 (53.7%) were business services, 78 (26.2%) were export laborers, 20 (6.7%) were peasants, and 18 (6.0%) were others.
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Malária/epidemiologia , Adulto , China/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Developing a simple, economical, and accurate diagnostic method has positive practical significance for the early prevention and intervention of Alzheimer's disease (AD). Herein, combining a closed bipolar electrode (BPE) chip with multicolor electrochemiluminescence (ECL) imaging technology, we constructed a low-voltage driven portable visualized ECL device for the early screening of AD. By introducing parallel resistance, the total resistance of the circuit was greatly reduced. A classical mixture of Ir(ppy)3 and Ru(bpy)32+ was used as multicolor emitters of the anode with TPrA as the co-reactant. Capture of amyloid-ß (Aß) through antigen-antibody recognition, and signal amplification by electroactive covalent organic frameworks (COF) probe at the cathode of BPE caused the significantly increased faradaic current. The electrical balance of the BPE system resulted in the change of the emission color from green to red at the anode. The ECL-BPE sensor shows good reproducibility and high sensitivity with detection limit of 1 pM by naked eye. The driving voltage is 3.0 V, which means the chip could be driven by two fifth batteries. The visualized ECL-BPE sensor provides a promising point-of-care testing (POCT) tool for the screening of Alzheimer's-related diseases in the early stage.
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Doença de Alzheimer , Técnicas Biossensoriais , Humanos , Doença de Alzheimer/diagnóstico , Medições Luminescentes/métodos , Reprodutibilidade dos Testes , Técnicas Biossensoriais/métodos , Biomarcadores , Eletrodos , Técnicas Eletroquímicas/métodosRESUMO
Single-atom catalyst (SAC), one of the most attractive catalysts in the field of energy conversion and storage, was proven as efficient accelerator for luminol-dissolved oxygen electrochemiluminescence (ECL) via the catalysis of oxygen reduction reaction (ORR). In this work, we synthesized heteroatom doping SACs of Fe-N/P-C for the catalysis of cathodic luminol ECL. The doping of P could lower the reaction energy barrier of the OH* reduction, and promote catalytic efficiency toward ORR. The formation of reactive oxygen species (ROS) during ORR triggered cathodic luminol ECL. Greatly enhanced ECL emission catalyzed by SACs proved that Fe-N/P-C exhibited higher catalytic activity to ORR compared with Fe-N-C. Since the system was highly dependent on oxygen, an ultra-sensitive detection of a typical antioxidant, ascorbic acid, was achieved with detection limit of 0.03 nM. This study provides possibility to greatly enhance the performance of ECL platform through rational tailoring of SACs via heteroatom doping.
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Intestinal ischemia/reperfusion (I/R) injury (IIRI) is associated with high prevalence and mortality rate. Recently, mesenchymal stem cell (MSC) therapy attracted more attentions. However, the function and regulatory mechanism of MSC-derived exosomal miRNAs during IIRI remain largely uninvestigated. The in vitro and in vivo IIRI models were established. MSC were characterized by immunofluorescent staining and flow cytometry. Purified exosomes were characterized by transmission electron microscopy (TEM), flow cytometry, and western blot. The expression of key molecules was detected by western blot and qRT-PCR. CCK-8, TUNEL, and transepithelial electrical resistance (TER) assays were employed to assess cell viability, apoptosis, and intestinal integrity, respectively. Pre-miR-34A m6 modification was evaluated by methylated RNA immunoprecipitation (MeRIP)-qPCR. RNA pull-down and RIP were used to validate the direct association between pre-miR-34A and IGF2BP3. MSC-derived exosomal miR-34a-5p alleviated OGD/R-induced injury. In addition, MSC ameliorated OGD/R-induced injury through METTL3 pathway. Mechanistic study revealed that miR-34a-5p was modulated by METTL3/IGF2BP3-mediated m6A modification in MSC. The in vitro and in vivo functional experiments revealed that MSC secreted exosomal miR-34a-5p and ameliorated IIRI through METTL3/IGF2BP3-mediated m6A modification of pre-miR-34A. MSC promoted the secretion of exosomal miR-34a-5p and improved intestinal barrier function through METTL3/IGF2BP3-mediated pre-miR-34A m6A modification.
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Exossomos , Células-Tronco Mesenquimais , MicroRNAs , Traumatismo por Reperfusão , Apoptose/genética , Exossomos/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo , Metiltransferases/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/metabolismoRESUMO
We developed an electrochemiluminescence (ECL) microscopy technique to image the structure-dependent electrocatalytic reactivity of bimetallic Pd-Au nanorods (NRs) at the single-particle level.