Electrochemiluminescence Research Articles

Rapid Preparation of a Self-Luminous Cd-Based Metal-Organic Framework Using AIEgen Ligands for High-Performance Electrochemiluminescence.

The design and synthesis of high-efficiency electrochemiluminescence (ECL) emitters hold great promise for a wide range of analytical applications. In this study, we developed a rapid and straightforward strategy to fabricate a self-luminous Cd-based metal-organic framework (Cd-MOF) using individual aggregation-induced emission ligands, specifically 1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)ethane (TPPE), within a few seconds. The rigid and directionally enriched metal node of Cd, along with the organic ligands, is formed within the Cd-MOF via coordination, effectively constraining the intramolecular free motions of TPPE and suppressing nonradiative relaxation. Additionally, the unique porous structure combined with the catalytic activity resulting from the incorporation of Cd2+, endow the Cd-MOF with 90-fold ECL enhancement compared to individual TPPE as more chromophores are electro-excited and more coreactants are catalyzed to produce luminescence. The as-made Cd-MOF amplifies the ECL performance by integrating ECL emitters and coreactant accelerators into a single entity, simplifying the sensing process. Leveraging the excellent ECL performance, we constructed a sensitive ECL sensor for hydroquinone based on competitive reactions, with a wide linear range from 200 nM to 1 mM and a satisfying detection limit as low as 80 nM.

Strong Electrochemiluminescence Response Derived from Ionic Chiral Covalent Organic Frameworks for Enantioselective Discrimination of Amino Acid Enantiomers via an Electrostatic Attraction Effect.

Porous chiral materials accompanied by electrochemiluminescence (ECL) activity are rarely reported for enantioselective discrimination because of the big challenges to integrate the stereogenic center and ECL-active unit in the backbone. In the present study, ionic chiral covalent organic frameworks (iCCOFs) consisting of the pyridinium unit as the ECL-active species were prepared by a facile strategy. We were amazed that such iCCOFs could display strong cathodic ECL responses. Meanwhile, the as-prepared ECL-active iCCOFs performed enantioselective ECL quenching toward amino acid enantiomers, attributed to the enhanced photoinduced electron transfer process derived from the formed complex between the iCCOFs and amino acids via an electrostatic attraction effect. The iCCOF with an (S)-configuration was prone to interact with l-amino acids, producing a lower ECL intensity. The maximum intensity ratio between the d- and l-enantiomers was 33.0. Finally, the enantiomeric compositions of the measured amino acids presented a good linear relation with the obtained ECL intensity, which was fit for the determination of samples with unknown enantiomeric purity. In brief, the obtained results convince us that this study advances a new generation of ECL-active iCCOFs and displays great potential in enantioselective sensing.

Designable Electrochemiluminescence Patterning for Renewable and Enhanced 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, 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.

Designable Electrochemiluminescence Patterning for Renewable and Enhanced 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, 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.

Highly sensitive detection of MMP-2 using an electrochemiluminescent biosensor enhanced by ladder-branch hybridization chain reaction.

Anadvanced electrochemiluminescence (ECL) biosensor was developedthat integrates T7 RNA polymerase amplification, ladder-branch hybridization chain reaction (HCR), and the precise targeting capabilities of CRISPR/Cas13a technology. The novelty of this research lies in the unique combination of these three cutting-edge technologies, which has not been previously utilized together in biosensing platforms, enabling highly sensitive and specific detection of biomolecules with exceptional precision. This innovative biosensor addresses the critical need for sensitive and specific detection of matrix metalloproteinase-2 (MMP-2), a key biomarker in cancer diagnostics. Through meticulous optimization of amplification and reaction conditions, the biosensor demonstrated remarkable sensitivity and specificity, achieving a detection limit as low as 6.34 aM, surpassing existing methodologies. The biosensor also exhibited excellent stability and reproducibility across multiple scans and maintained consistent functionality over an extended period, highlighting its reliability for practical applications. The effectiveness of the biosensor was validated using real samples, demonstrating its capability to accurately quantify MMP-2 in complex biological matrices with high recovery and minimal interference. The integration of isothermal amplification and CRISPR/Cas13a within the ECL biosensor platform represents a significant advancement in molecular diagnostics, offering a powerful tool for real-time monitoring of MMP-2. This combination of technologies sets the platform apart from traditional methods, marking a significant step forward in biosensor innovation. This biosensor holds substantial promise for revolutionizing cancer diagnostics and facilitating personalized treatment strategies, ultimately aiming to improve patient outcomes in cancer care. Future research may explore further enhancements and applications of this biosensor in various clinical settings.

Tetraphenylethene-Based Covalent Organic Polymers with Aggregation-Induced Electrochemiluminescence for Highly Sensitive Bacterial Biosensors.

Tetraphenylethene (TPE), which usually serves as aggregation-induced emission and aggregation-induced electrochemiluminescence fluorophores, has been widely applied in fabricating fluorescent nanomaterials and biosensors. However, it is still a tremendous challenge to prepare well-controlled TPE aggregates with strong fluorescence (FL) and electrochemiluminescence (ECL). In this study, we constructed a bacterial ECL biosensing platform with high sensitivity based on TPE-based covalent organic polymer (COP) nanoparticles synthesized by a simple Menschutkin reaction strategy to employ bromide group-carrying molecules and 1,1,2,2-tetrakis(4-(pyridine-4-yl)phenyl)ethene as the cross-linking agent and the emissive moiety, respectively. The ECL Escherichia coli biosensor had high sensitivity, a low limit of detection (0.19 CFU mL-1), a wide linear range (1 × 102-5 × 106 CFU mL-1), and good selectivity. The excellent properties of the bacterial biosensor could be attributed to the uniform spherical COP nanoparticles with enhanced FL and ECL signals, the maximal ECL efficiency of which was 8.4-fold higher than that of the typical tris(bipyridine) ruthenium(II) emitter. The FL and ECL intensities of the TPE-based COP nanoparticles could be adjusted by varying bromide group-carrying molecules and thus regulating their energy gap between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) orbitals. The TPE-based COP nanoparticles with strong FL and ECL intensities pave a promising avenue to construct highly sensitive bacterial ECL biosensors for the large-scale screening of disease-causing bacteria.

Highly Active Oxygen Evolution Reaction of NiMoO4 Sub-1nm Nanowires Boosts Luminol Electrochemiluminescence.

In recent years, there has been an increasing research focus on the luminol-H2O electrochemiluminescence (ECL) system due to its ability to address the instability and toxicity of H2O2, which are common issues associated with the conventional luminol-H2O2 ECL system. To enhance the ECL efficiency of the luminol-H2O system, researchers have developed electrocatalytic materials with exceptional oxygen evolution reaction (OER) properties to facilitate water electrolysis into O2 to produce reactive oxygen species (ROS) and act as co-reactant promoters. However, most of these materials are characterized by their nanoscale or microscale dimensions, resulting in relatively large sizes and low specific surface areas, which hinder the application of the luminol-H2O system. To address this challenge, nickel molybdate sub-1nm nanowires (NiMoO4 S1 NWs) with a large specific surface area is synthesized that can offer many active sites to enhance the performance of the OER to boost the ECL of luminol. This study demonstrates that the large amount of ROS generated by the OER of NiMoO4 S1 NWs play a crucial role in enhancing the ECL intensity of luminol. Finally, a NiMoO4 S1 NWs-based ECL biosensor for the highly sensitive detection of the nucleocapsid proteins of SARS-CoV-2 is successfully constructed.

RuSiNPs@N,S-GQDs as self-enhanced anodic electrochemiluminescent immunobeacons for the highly sensitive quantitation of okadaic acid in shellfish.

Acompetitive electrochemiluminescence (ECL) immunosensor isproposed to accurately and rapidly assess okadaic acid (OA) levels in shellfish using a novel self-reinforced solid-state ECL marker, which is essential for ensuring seafood safety. Graphene quantum dots doped with nitrogen and sulfur (N,S-GQDs) were synthesized, for the first time, through the electrolysis of graphite in 3-(N-morpholine) propane sulfonic acid solution. Intriguingly, these N,S-GQDs exhibited exceptional co-reactant properties, significantly enhancing the anodic ECL performance of Ru(bpy)32+ in a phosphate-buffered saline solution. Following the functionalization of Ru(bpy)32+-doped silica nanoparticles (RuSiNPs) with poly(diallyldimethylammonium) chloride, we achieved a well-dispersed assembly of N,S-GQDs on the exterior of the RuSiNPs through electrostatic interactions. Importantly, the core-shell structure of RuSiNPs@N,S-GQDs efficiently encapsulated both the luminophore and co-reactant, thus improving the transfer rates of electrons, shorting interaction distances, and reducing energy loss during light emission. Leveraging this "bright" ECL beacon, theECL immunosensor demonstrated remarkable analytical performance, yielding a low half maximal inhibitory concentration (IC50) of 0.14ngmL-1, an extensive linear range spanning 0.003-40ngmL-1, and impressively low limit of detection of 0.001ngmL-1 for OA determination.

NiFe Nanoalloy Electrocatalyst as a Coreaction Accelerator for Enhancing Biomarker Electrochemiluminescence Imaging Detection.

The development of coreaction accelerators with excellent performance is crucial for improving electrochemiluminescence (ECL) performance. In this study, a NiFe nanoalloy electrocatalyst (NiFe-NAEC) was used as a coreaction accelerator to promote persulfate activation, resulting in a 44-fold increase in the ECL intensity of flower-like Zn-3,4,9,10-perylenetetracarboxylate (FL-Zn-PTC). Moreover, the synergistic combination of NiFe-NAEC and silver nanoparticles led to a 134-fold increase in the ECL intensity of FL-Zn-PTC, with a 6275% improvement in the ECL efficiency compared with a reference system containing Ru-bpy/K2S2O8. Consequently, a sensor was constructed for the visual detection of amino-terminal pro-brain natriuretic peptide. This sensor exhibited high sensitivity and provided intuitive results within a linear range from 0.01 to 1000 pg/mL, with a detection limit of 2.1 fg/mL. Overall, this study presents a strategy that integrates an electrocatalytic coreaction accelerator with synergistic enhancement to improve ECL performance. This approach has the potential to expand the range of emitter materials and advance ECL technology.

Highly specific detection of ROR1 cancer biomarker with bipolar electrochemiluminescence.

An electrochemiluminescence (ECL) detection system is presented integrated with a bipolar electrode system for sensitive cancer diagnosis. In order to achieve the highest electrical conductivity and redox-active surface area, MXene was chosen as the material for the bipolar electrode. As part of the detection process, the anodic pole of the bipolar electrode was modified with the receptor tyrosine kinase like orphan receptor 1 (ROR1) antibody, followed by an immunoassay using the ROR1 antibody-modified Ag triangle that was identified as significantly enhancing ECL. We measured the ECL of luminol using the anode pole of BPE as an analytical signal in the presence of H2O2. Additionally, 3D-printed microchannels were used to fabricate the BPE system, to reduce the quantity of sample required. It has been shown that the present immunosensors are low-cost and sensitive in detecting types of cancer, with an extended linear range of 10 fg mL-1 to 1 µg mL-1 in the analysis of synthetic samples and achieving an accuracy of ~ 90% in diagnosing ten unknown real samples.

An electrochemiluminescence sensor for ultrasensitive determination of tyrosine based on ceria nanomaterial as a novel luminophor

BackgroudRecently, optical nanomaterials have attracted much attention in the field of electrochemiluminescence (ECL). Nanostructured ceria possessed unique optical properties, and it's always used for constructing ECL sensor as catalyst for improving sensing performance, while the ECL property of ceria is rarely studied. In fact, it could be the potential candidate for applying in ECL sensors based on size and shape dependency optical property caused by the quantum scale effects. Therefore, new simple and efficient ceria nanomaterial used as luminophor for constructing the ECL sensor have aroused more research interest and motivation. (91 words). ResultsIn the work, three kinds of nanostructured ceria, ceria nano-cube (CeO2-NC), ceria nano-rods (CeO2-NR) and ceria nano-particle (CeO2-NP), have been prepared by hydrothermal method, and CeO2-NC with the less oxygen vacancy has the highest ECL signal. Moreover, how the shape affects the ECL property was investigated in detail, especially the oxygen vacancy on the surface of the ceria. The less of oxygen vacancy content of CeO2 nanomaterials is more favorable the ECL reaction. Furthermore, a novel ECL sensor was constructed based on reduced graphene oxide (rGO), Au nano-particle (AuNPs) and CeO2-NC for Tyrosine (Tyr) determination owing to the electron transform between the luminous of ceria and Tyr resulting in the cathodic ECL intensity quenched correspondingly, and it has possessed excellent sensing performance with a linear range of 0.005–20 nmol/L and the limit of detection (LOD) value of 1.7 fmol/L (141 words) Significance and noveltyThe proposed method demonstrated excellent selectivity and ultra-sensitivity toward Tyr, which had been used for the determination of Tyr in human serum successfully, possessing outstanding analytical performance. Therefore, nanostructured ceria is a new category of efficient and promising luminophore, which would open new avenues for the potential application in the field of ECL sensing for clinical diagnosis. (57 words).

Dual Gold Nanostructures-Based Stretchable Electrochemiluminescence Sensors for Hydrogen Peroxide Monitoring in Endothelial Mechanotransduction.

Hydrogen peroxide (H2O2) release during blood flow is commonly provoked by the cyclic stretch and dynamic shear stress of endothelial cells and is of vital significance for maintaining vascular function. Flexible and stretchable electrochemical sensors show great capability in retrieving mechanical stimulation-induced H2O2 variation; however, cell secretions, especially electroactive constituents' interferences, remain a big concern for sensing accuracy. Herein, we developed a stretchable electrochemiluminescence (ECL) sensor by synthesizing L012-reduced gold nanospheres and decorating them onto a polydimethylsiloxane film-supported gold nanotubes substrate (Au NTs/PDMS) to form dual gold nanostructure-modified meshwork interface. Given the specific reaction between L012 and H2O2, the as-prepared Au-L012/Au NTs/PDMS exhibited outstanding selectivity toward H2O2 quantification. Through culturing human umbilical vein endothelial cells (HUVECs), real-time monitoring of transient H2O2 release from mechanically sensitive HUVECs in stretching states was realized. This work successfully incorporated the ECL sensing model into in situ cellular sensing, therefore expanding the application mode of the ECL approach for health care and biomedical investigation.

Urine lipoarabinomannan concentrations among HIV-negative adults with pulmonary or extrapulmonary tuberculosis disease in Vietnam.

Lipoarabinomannan (LAM) is a promising target biomarker for diagnosing subclinical and clinical tuberculosis (TB). Urine LAM (uLAM) testing using rapid diagnostic tests (RDTs) has been approved for people living with HIV (PLWH), however there is limited data regarding uLAM levels in HIV-negative (HIV-ve) adults with clinical TB. We conducted a clinical study of adults presenting with clinical TB-related symptoms at the National Lung Hospital in Hanoi, Vietnam. The uLAM concentrations were measured using electrochemiluminescent (ECL) immunoassays and compared to a microbiological reference standard (MRS) using GeneXpert Ultra and TB culture testing. Estimated uLAM concentrations above plate specific calculated limit of detection (LOD) were considered uLAM positive. Additional microbiological testing was conducted for possible extrapulmonary TB (EPTB). Among 745 participants enrolled, 335 (44.9%) participants with presumptive pulmonary TB (PTB) and 6 (11.3%) participants with presumptive EPTB had confirmed TB disease. Overall, the S/A antibody pair had a sensitivity of 39% (95% Confidence Interval [CI] 0.33, 0.44) and a specificity of 97% (95% CI 0.96, 0.99) compared to the MRS. The F/A antibody pair had a sensitivity of 41% (95% CI 0.35, 0.47) and a specificity of 79% (95% CI 0.75, 0.84). S/A provided greater discriminatory ability compared to F/A for both individuals with presumptive PTB (AUROC: 0.74 vs 0.63, p<0.0001) and presumptive EPTB (0.76 vs 0.54, p = 0.045) when using the MRS. Among HIV-ve participants in an adult cohort in Vietnam, the concentrations of uLAM remained relatively low for people with clinical TB, which may present challenges for improving RDT sensitivity.

Integrating All-rounder TiO2 Accelerated Electrochemiluminescence with Dual-Quenching PDA@COF Probes for Sensitive Quantification and Protein Profiling of Tumorous Exosomes.

Exosomes have been perceived as promising biomarkers for noninvasive cancer diagnosis and treatment monitoring. However, the sensitive and accurate quantification and phenotyping of exosomes remains challenging. Herein, a versatile electrochemiluminescence (ECL) aptasensor was proposed for the sensitive analysis of tumorous exosomes. Specifically, a ternary nanohybrid (Ru-HAuTiO2), by covalently linking ECL luminophore Ru(dcbpy)32+ with gold nanoparticles (AuNPs)-decorated hollow urchin-like TiO2 (HTiO2), was ingeniously designed as a highly luminescent and self-enhanced ECL nanoemitter. Notably, the porous HTiO2 played an "all-rounder" role, including the carrier for ECL luminophores and AuNPs, coreaction accelerator, and specific exosome capturing scaffold through Ti-phosphate coordination interaction. On the other hand, a polydopamine modified covalent organic framework (PDA@COF) was employed as a quencher to remarkably attenuate the ECL of Ru-HAuTiO2 through a dual-quenching mechanism, and further labeled with a specific aptamer (Apt) of exosomal surface protein. Based on forming a Ru-HAuTiO2/exosome/Apt-PDA@COF sandwich structure on the electrode, a "signal on-off" ECL platform for tumorous exosomes was constructed, realizing sensitive detection within the range of 3.1 × 103 particles/mL to 1 × 108 particles/mL and a low limit of detection of 1.41 × 103 particles/mL, achieving phenotypic profiling of surface proteins on different tumorous exosomes. This work provides a promising alternative method for the detection and analysis of exosomes.

Hexagonal Prism-Shaped AIE-Active MOFs as Coreactant-Free Electrochemiluminescence Luminophores Coupled with Hollow Cu2-xO@Pd Heterostructures as Efficient Quenching Probes for Sensitive Biosensing.

For most self-luminous metal-organic framework (MOF)-involved electrochemiluminescence (ECL) systems, the integration of exogenous coreactants is indispensable to promote ECL efficiency. However, the introduction of a coreactant into an electrolyte would result in poor stability, thereby inevitably affecting analytical accuracy. Herein, by employing aggregation-induced emission luminogens as ligands, we first synthesized one hexagonal prism-shaped MOF that displays robust and steady ECL signal without an exogenous coreactant. Furthermore, adenosine triphosphate (ATP), as the target analyte, can be fixed on the electrode surface directly owing to the strong coordination between Zr4+ and phosphate groups. According to the ECL resonance energy transfer effect, hollow Cu2-xO@Pd heterostructures are conveniently prepared and act as efficient quenching probes. Remarkably, the resultant urchin-like hollow structure could provide more active sites to anchor ATP aptamers, thus enhancing the ECL quenching efficiency. In this manner, an elaborate coreactant-free ECL system was developed to detect ATP, which demonstrates a remarkable detection limit of 0.17 nM, as well as excellent stability and reproducibility. The present work offers significant enlightenment for the further evolution of advanced ECL systems integrated with MOF-based luminophores.

Photoinduced Electrochemiluminescence Immunoassays.

Optimization of electrochemiluminescence (ECL) immunoassays is highly beneficial for enhancing clinical diagnostics. A major challenge is the improvement of the operation conditions required for the bead-based immunoassays using the typical [Ru(bpy)3]2+/tri-n-propylamine (TPrA) system. In this study, we report a heterogeneous immunoassay based on near-infrared photoinduced ECL, which facilitates the imaging and quantitative analysis of [Ru(bpy)3]2+-modified immunobeads at low anodic potential. The photovoltage generated by the photoanode under near-infrared light promotes oxidation processes at the electrode/electrolyte interface, thus considerably lowering the onset potential for both TPrA oxidation and ECL emission. The anti-Stokes shift between the excitation light (invisible to the human eyes) and the visible emitted light results in a clear and stable signal from the immunobeads. In addition, it offers the possibility of site-selective photoexcitation of the ECL process. This approach not only meets the performance of traditional ECL immunoassays in accuracy but also offers the additional benefits of lower potential requirements and enhanced stability, providing a new perspective for the optimization of commercial immunoassays.

Dual-signal immunosensor based on aggregation-induced electrochemiluminescence resonance energy transfer of La-MOF and low cathodic excitation potential of g-C3N4@AuNPs for the quantitation of human serum amyloid A

We report on the development of a dual-signal electrochemiluminescence (ECL) immunosensor for the quantitation of human serum amyloid A (SAA). The immunosensor comprises g-C3N4@AuNPs as the cathode and a lanthanum-based metal organic framework (La-MOF) as the anode, the latter of which utilizes aggregation-induced electrochemiluminescence (AIECL) to overcome the otherwise poor ECL intensity of H4TBAPy ligands at the electrode surface. Furthermore, the rigid MOF structure significantly improved the fluorescence quantum yield, as well as the fluorescence and ECL emission, of the La-MOF compared to H4TBAPy. The g-C3N4@AuNPs exhibits an ultrathin nanosheet structure with a low cathodic excitation potential of −0.72V. When the dual-signal ECL immunosensor was employed to detect SAA, the difference between the anodic and cathodic ECL signals exhibited a strong linear relationship with the logarithm of the SAA concentration in the range of 100 fg/mL–200ng/mL, with a detection limit of 24.5 fg/mL.

Immunosensing of Cardiac Troponin I (cTnI) Using a Two-Electrode Electrochemiluminescence Platform with Near Persisting Luminescence Generated on a Ru(bpy)32+-Tripropylamine System.

An economical, rapid, and ultrasensitive detection of biomolecules in clinical settings is very crucial, particularly for the early detection of Cardiac Troponin I (cTnI), which is the gold standard biomarker for Acute Myocardial Infarction (AMI). Electrochemiluminescence (ECL) has risen in prominence as an important technique for in vitro diagnosis and detection by virtue of its high sensitivity reaching a femtomolar level. This study introduces an economically feasible nanoplatform for ECL immunosensing, consisting of a gold nanoparticle (AuNP) with Ru(bpy)32+ and tripropylamine (TPA) system, which is a potential ECL luminophore and coreactant system. AuNPs serve the role of an ECL signal enhancer as well as the carrier of antibody, which enables the creation of a label-free immunosensor for antigen-antibody interactions. The prepared immunosensor detected cTnI with a detection limit (LOD) of 0.03 ng/mL. This potential immunosensor provides appreciable results in the detection of cTnI from spiked real serum analysis, which shows its potential application in low-resource clinical settings.

Sensitive detection of K-ras gene by a dual-mode “on-off-on” sensor based on bipyridine ruthenium-MOF and bis-enzymatic cleavage technology

This study developed a dual-mode “on-off-on” sensor based on a bipyridine ruthenium metal–organic framework (Ru-MOF) and dual enzyme cleavage technology for the sensitive detection of the K-ras gene. The sensor combines electrogenerated chemiluminescence (ECL) and fluorescence (FL) detection modes, achieving high sensitivity and specificity in detecting the K-ras gene through catalytic hairpin assembly (CHA) and dual enzyme cleavage reactions. Experimental results showed that the detection limits for the K-ras gene were 0.044 fM (ECL) and 0.16 fM (FL), demonstrating excellent selectivity and stability during detection. Through testing actual samples, the sensor has shown potential for application in complex biological environments. This method offers an efficient and reliable new tool for cancer diagnosis and treatment.

Unary Au Nanocrystal with Prestored Electrons and Intrinsic Low Hole-Injected Potential for Low-Triggering Potential Electrochemiluminescence.

Screening a novel electrochemiluminescence (ECL) system and lowering the ECL triggering potential are essential to ECL evolution. Herein, the near-infrared (NIR) ECL system with low-triggering potential ECL was constructed with weakly reductive tert-butylamine borane as coreactant and mercaptosuccinic acid/citrate (MSA/Cit)-capped Au (MSA/Cit@AuNCs) as luminophores. Toxic-element-free and dual-ligand MSA/Cit@AuNCs were prepared via ligand exchange and utilized as a model for developing unary metal NCs-based luminophores with more enhanced ECL performance than monoligand Au nanocrystals (AuNCs), which exhibited a two hole-injected process at around 0.48 and 0.80 V, respectively. Beneficial to the intrinsic low hole-injected potential of AuNCs, MSA/Cit@AuNCs exhibited similar low-triggering ECL potential at around 0.57 V with the participation of series coreactants or not, originating from the recombination of an internal prestored electron within the conduction band (CB) and electroinjected holes at around 0.25 V. Furthermore, the enhanced low-triggering potential around 0.57 V and NIR ECL around 835 nm of MSA/Cit@AuNCs was eventually obtained with the reductive tert-butylamine borane or N2H4·H2O containing a -C-N single-bond structure merely as coreactant. The low-triggering potential ECL of MSA/Cit@AuNCs/tert-butylamine borane system at 0.57 V can be harnessed to selectively determine a carcinoembryonic antigen (CEA) with one linear range spanning from 2 to 20000 fg/mL and a limit of detection of 0.33 fg/mL (S/N = 3). This study will contribute to a more comprehensive understanding of the ECL mechanism in terms of both regulating NCs and selecting coreactants.