Chemi-Northern: a versatile chemiluminescent northern blot method for analysis and quantitation of RNA molecules.

This report describes a chemiluminescence-based detection method for RNAs on northern blots, designated Chemi-Northern. This approach builds on the simplicity and versatility of northern blotting, while dispensing of the need for expensive and cumbersome radioactivity. RNAs are first separated by denaturing gel electrophoresis, transferred to a nylon membrane, and then hybridized to a biotinylated RNA or DNA antisense probe. Streptavidin conjugated with horseradish peroxidase and enhanced chemiluminescence substrate are then used to detect the probe bound to the target RNA. Our results demonstrate the versatility of this method in detecting natural and engineered RNAs expressed in cells, including messenger and noncoding RNAs. We show that Chemi-Northern detection is sensitive and fast, detecting attomole amounts of RNA in as little as 1 sec, with high signal intensity and low background. The dynamic response displays excellent linearity. Using Chemi-Northern, we measure the reproducible, statistically significant reduction of mRNA levels by human sequence-specific RNA-binding proteins, PUM1 and PUM2. Additionally, we measure the interaction of the poly(A) binding protein, PABPC1, with polyadenylated mRNA. Thus, the Chemi-Northern method provides a versatile, simple, and cost-effective method to enable researchers to analyze expression, processing, binding, and decay of RNAs.

Design and synthesis of a small molecular NIR-II chemiluminescence probe for in vivo-activated H2S imaging.

Chemiluminescence (CL) with the elimination of excitation light and minimal autofluorescence interference has been wieldy applied in biosensing and bioimaging. However, the traditional emission of CL probes was mainly in the range of 400 to 650 nm, leading to undesired resolution and penetration in a biological object. Therefore, it was urgent to develop CL molecules in the near-infrared window [NIR, including NIR-I (650 to 900 nm) and near-infrared-II (900 to 1,700 nm)], coupled with unique advantages of long-time imaging, sensitive response, and high resolution at depths of millimeters. However, no NIR-II CL unimolecular probe has been reported until now. Herein, we developed an H2S-activated NIR-II CL probe [chemiluminiscence donor 950, (CD-950)] by covalently connecting two Schaap's dioxetane donors with high chemical energy to a NIR-II fluorophore acceptor candidate via intramolecular CL resonance energy transfer strategy, thereby achieving high efficiency of 95%. CD-950 exhibited superior capacity including long-duration imaging (~60 min), deeper tissue penetration (~10 mm), and specific H2S response under physiological conditions. More importantly, CD-950 showed detection capability for metformin-induced hepatotoxicity with 2.5-fold higher signal-to-background ratios than that of NIR-II fluorescence mode. The unimolecular NIR-II CL probe holds great potential for the evaluation of drug-induced side effects by tracking its metabolites in vivo, further facilitating the rational design of novel NIR-II CL-based detection platforms.

In vivo three-dimensional brain imaging with chemiluminescence probes in Alzheimer's disease models.

Optical three-dimensional (3D) molecular imaging is highly desirable for providing precise distribution of the target-of-interest in disease models. However, such 3D imaging is still far from wide applications in biomedical research; 3D brain optical molecular imaging, in particular, has rarely been reported. In this report, we designed chemiluminescence probes with high quantum yields, relatively long emission wavelengths, and high signal-to-noise ratios to fulfill the requirements for 3D brain imaging in vivo. With assistance from density-function theory (DFT) computation, we designed ADLumin-Xs by locking up the rotation of the double bond via fusing the furan ring to the phenyl ring. Our results showed that ADLumin-5 had a high quantum yield of chemiluminescence and could bind to amyloid beta (Aß). Remarkably, ADLumin-5's radiance intensity in brain areas could reach 4 × 107 photon/s/cm2/sr, which is probably 100-fold higher than most chemiluminescence probes for in vivo imaging. Because of its strong emission, we demonstrated that ADLumin-5 could be used for in vivo 3D brain imaging in transgenic mouse models of Alzheimer's disease.

A chemical timer approach to delayed chemiluminescence.

Although the onset time of chemical reactions can be manipulated by mechanical, electrical, and optical methods, its chemical control remains highly challenging. Herein, we report a chemical timer approach for manipulating the emission onset time of chemiluminescence (CL) reactions. A mixture of Mn2+, NaHCO3, and a luminol analog with H2O2 produced reactive oxygen species (ROS) radicals and other superoxo species (superoxide containing complex) with high efficiency, accompanied by strong and immediate CL emission. Surprisingly, the addition of thiourea postponed CL emission in a concentration-dependent manner. The delay was attributed to a slow-generation-scavenging mechanism, which was found to be generally applicable not only to various types of CL reagents and ROS radical scavengers but also to popular chromogenic reactions. The precise regulation of CL kinetics was further utilized in dynamic chemical coding with improved coding density and security. This approach provides a powerful platform for engineering chemical reaction kinetics using chemical timers, which is of application potential in bioassays, biosensors, CL microscopic imaging, microchips, array chips, and informatics.

Development of a chemiluminescence assay for tissue plasminogen activator inhibitor complex and its applicability to gastric cancer.

BACKGROUND: Venous thromboembolism (VTE), is a noteworthy complication in individuals with gastric cancer, but the current diagnosis and treatment methods lack accuracy. In this study, we developed a t-PAIC chemiluminescence kit and employed chemiluminescence to detect the tissue plasminogen activator inhibitor complex (t-PAIC), thrombin-antithrombin III complex (TAT), plasmin-α2-plasmin inhibitor complex (PIC) and thrombomodulin (TM), combined with D-dimer and fibrin degradation products (FDP), to investigate their diagnostic potential for venous thrombosis in gastric cancer patients. The study assessed variations in six indicators among gastric cancer patients at different stages. RESULTS: The t-PAIC reagent showed LOD is 1.2 ng/mL and a linear factor R greater than 0.99. The reagents demonstrated accurate results, with all accuracy deviations being within 5%. The intra-batch and inter-batch CVs for the t-PAIC reagent were both within 8%. The correlation coefficient R between this method and Sysmex was 0.979. Gastric cancer patients exhibited elevated levels of TAT, PIC, TM, D-D, FDP compared to the healthy population, while no significant difference was observed in t-PAIC. In the staging of gastric cancer, patients in III-IV stages exhibit higher levels of the six markers compared to those in I-II stages. The ROC curve indicates an enhancement in sensitivity and specificity of the combined diagnosis of four or six indicators. CONCLUSION: Our chemiluminescence assay performs comparably to Sysmex's method and at a reduced cost. The use of multiple markers, including t-PAIC, TM, TAT, PIC, D-D, and FDP, is superior to the use of single markers for diagnosing VTE in patients with malignant tumors. Gastric cancer patients should be screened for the six markers to facilitate proactive prophylaxis, determine the most appropriate treatment timing, ameliorate their prognosis, decrease the occurrence of venous thrombosis and mortality, and extend their survival.

Bioluminescence - The Vibrant Glow of Nature and its Chemical Mechanisms.

Bioluminescence, the mesmerizing natural phenomenon where living organisms produce light through chemical reactions, has long captivated scientists and laypersons alike, offering a rich tapestry of insights into biological function, ecology, evolution as well as the underlying chemistry. This comprehensive introductory review systematically explores the phenomenon of bioluminescence, addressing its historical context, geographic dispersion, and ecological significance with a focus on their chemical mechanisms. Our examination begins with terrestrial bioluminescence, discussing organisms from different habitats. We analyze thefireflies of Central Europe's meadows and the fungi in the Atlantic rainforest of Brazil. Additionally, we inspect bioluminescent species in New Zealand, specifically river-dwelling snails and mosquito larvae found in Waitomo Caves. Our exploration concludes in the Siberian Steppes, highlighting the area's luminescent insects and annelids. Transitioning to the marine realm, the second part of this review examines marine bioluminescent organisms. We explore this phenomenon in deep-sea jellyfish and their role in the ecosystem. We then move to Toyama Bay, Japan, where seasonal bioluminescence of dinoflagellates and ostracods present a unique case study. We also delve into the bacterial world, discussing how bioluminescent bacteria contribute to symbiotic relationships. For each organism, we contextualize its bioluminescence, providing details about its discovery, ecological function, and geographical distribution. A special focus lies on the examination of the underlying chemical mechanisms that enables these biological light displays. Concluding this review, we present a series of practical bioluminescence and chemiluminescence experiments, providing a resource for educational demonstrations and student research projects. Our goal with this review is to provide a summary of bioluminescence across the diverse ecological contexts, contributing to the broader understanding of this unique biological phenomenon and its chemical mechanisms serving researchers new to the field, educators and students alike.

High pre-Delta and early-Omicron SARS-CoV-2 seroprevalence detected in dried blood samples from Kinshasa (D.R. Congo).

Studies on the impact of the COVID-19 pandemic in sub-Saharan Africa have yielded varying results, although authors universally agree the real burden surpasses reported cases. The primary objective of this study was to determine SARS-CoV-2 seroprevalence among patients attending Monkole Hospital in Kinshasa (D.R. Congo). The secondary objective was to evaluate the analytic performance of two chemiluminescence platforms: Elecsys® (Roche) and VirClia® (Vircell) on dried blood spot samples (DBS). The study population (N = 373) was recruited in two stages: a mid-2021 blood donor cohort (15.5% women) and a mid-2022 women cohort. Crude global seroprevalence was 61% (53.9%-67.8%) pre-Delta in 2021 and 90.2% (84.7%-94.2%) post-Omicron in 2022. Anti-spike (S) antibody levels significantly increased from 53.1 (31.8-131.3) U/mL in 2021 to 436.5 (219.3-950.5) U/mL in 2022 and were significantly higher above 45 years old in the 2022 population. Both platforms showed good analytic performance on DBS samples: sensitivity was 96.8% for IgG (antiN/S) (93.9%-98.5%) and 96.0% (93.0%-98.0%) for anti-S quantification. These results provide additional support for the notion that exposure to SARS-CoV-2 is more widespread than indicated by case-based surveillance and will be able to guide the pandemic response and strategy moving forward. Likewise, this study contributes evidence to the reliability of DBS as a tool for serological testing and diagnosis in resource-limited settings.

Plant acclimation to ionising radiation requires activation of a detoxification pathway against carbonyl-containing lipid oxidation products.

Ionising γ radiation produces reactive oxygen species by water radiolysis, providing an interesting model approach for studying oxidative stress in plants. Three-week old plants of Arabidopsis thaliana were exposed to a low dose rate (25 mGy h-1) of γ radiation for up to 21 days. This treatment had no effect on plant growth and morphology, but it induced chronic oxidation of lipids which was associated with an accumulation of reactive carbonyl species (RCS). However, contrary to lipid peroxidation, lipid RCS accumulation was transient only, being maximal after 1 day of irradiation and decreasing back to the initial level during the subsequent days of continuous irradiation. This indicates the induction of a carbonyl-metabolising process during chronic ionising radiation. Accordingly, the γ-radiation treatment induced the expression of xenobiotic detoxification-related genes (AER, SDR1, SDR3, ALDH4, and ANAC102). The transcriptomic response of some of those genes (AER, SDR1, and ANAC102) was deregulated in the tga256 mutant affected in three TGAII transcription factors, leading to enhanced and/or prolonged accumulation of RCS and to a marked inhibition of plant growth during irradiation compared to the wild type. These results show that Arabidopsis is able to acclimate to chronic oxidative stress and that this phenomenon requires activation of a carbonyl detoxification mechanism controlled by TGAII. This acclimation did not occur when plants were exposed to an acute γ radiation stress (100 Gy) which led to persistent accumulation of RCS and marked inhibition of plant growth. This study shows the role of secondary products of lipid peroxidation in the detrimental effects of reactive oxygen species.

Microfluidic paper-based chemiluminescence sensing platform based on functionalized CaCO3 for time-resolved multiplex detection of avian influenza virus biomarkers.

Multiplex detection can enhance diagnostic precision and improve diagnostic efficiency, providing important assistance for epidemiological investigation and epidemic prevention. There is a great need for multi-detection sensing platforms to accurately diagnose diseases. Herein, we reported a µPAD-based chemiluminescence (CL) assay for ultrasensitive multiplex detection of AIV biomarkers, based on three DNAzyme/Lum/PEI/CaCO3. Three time-resolved CL signals were sequentially generated with detection limits of 0.32, 0.34, and 0.29 pM for H1N1, H7N9, and H5N1, respectively, and with excellent selectivity against interfering DNA. The recovery test in human serum displayed satisfactory analysis capabilities for complex biological samples. The µPAD-based CL assay achieved multiplex detection within 70 s, with a high time resolution of 20 s. The proposed strategy has the advantages of low cost, high sensitivity, good selectivity, and wide time resolution, the µPAD-based CL assay has shown great potential in the early and accurate diagnosis of diseases.

Synthesis of Multi-Functional Graphene Monolayers via Bipolar Electrochemistry.

Graphene has gained substantial research interest in many fields due to its remarkable properties among many other two-dimensional materials. In this study, we propose a wireless electrochemical approach, bipolar electrochemistry, for the precise modification of single layers of graphene at predefined locations, such as distinct edges or corners, with a variety of metals or polymers, thus enabling the elaboration of multi-functional monolayer graphene sheets. We illustrate the concept e. g. by depositing multiple metals, or platinum and a catalyst-containing porous polymer on the same graphene sheet, but at separate corners. This configuration allows activating chemiluminescence on the polymer spot, and simultaneously generates the driving force for autonomous motion on the Pt side through the catalytic decomposition of hydrogen peroxide into oxygen bubbles. This integration of different chemical features on the same object, exemplified by these proof-of-principle experiments, enhances the functionality of two-dimensional materials, paving the way for the use of these hybrid materials for a variety of applications, ranging from sensing and catalysis to targeted delivery.

Field Quantification of Hydroxyl Radicals by Flow-Injection Chemiluminescence Analysis with a Portable Device.

Hydroxyl radical (•OH) is a powerful oxidant abundantly found in nature and plays a central role in numerous environmental processes. On-site detection of •OH is highly desirable for real-time assessments of •OH-centered processes and yet is restrained by a lack of an analysis system suitable for field applications. Here, we report the development of a flow-injection chemiluminescence analysis (FIA-CL) system for the continuous field detection of •OH. The system is based on the reaction of •OH with phthalhydrazide to generate 5-hydroxy-2,3-dihydro-1,4-phthalazinedione, which emits chemiluminescence (CL) when oxidatively activated by H2O2 and Cu3+. The FIA-CL system was successfully validated using the Fenton reaction as a standard •OH source. Unlike traditional absorbance- or fluorescence-based methods, CL detection could minimize interference from an environmental medium (e.g., organic matter), therefore attaining highly sensitive •OH detection (limits of detection and quantification = 0.035 and 0.12 nM, respectively). The broad applications of FIA-CL were illustrated for on-site 24 h detection of •OH produced from photochemical processes in lake water and air, where the temporal variations on •OH productions (1.0-12.2 nM in water and 1.5-37.1 × 107 cm-3 in air) agreed well with sunlight photon flux. Further, the FIA-CL system enabled field 24 h field analysis of •OH productions from the oxidation of reduced substances triggered by tidal fluctuations in coastal soils. The superior analytical capability of the FIA-CL system opens new opportunities for monitoring •OH dynamics under field conditions.

Combining High-Resolution Mass Spectrometry and Chemiluminescence Analysis to Characterize the Composition and Fate of Total N-Nitrosamines in Wastewater Treatment Plants.

Monitoring the prevalence and persistence of N-nitrosamines and their precursors in wastewater treatment plants (WWTPs) and effluent-receiving aquatic compartments is a priority for utilities practicing wastewater recycling or exploiting wastewater-impacted source waters. In this work, we developed an analytical framework that combines liquid chromatography-high-resolution mass spectrometry (LC-HRMS) with acidic triiodide-chemiluminescence analysis to characterize the composition and fate of total N-nitrosamines (TONO) and their precursors along the treatment trains of eight WWTPs in New York. Through the parallel application of LC-HRMS and chemiluminescence methods, the TONO scores for 41 N-nitrosamines containing structurally diverse substituents on their amine nitrogen were derived based on their solid-phase extraction recoveries and conversion efficiencies to nitric oxide. Correcting the compositional analysis of TONO using the TONO scores of target N-nitrosamines refined the assessment of the reduction or accumulation of TONO and their precursors across treatment steps in WWTPs. Nontargeted analysis prioritized seven additional N-nitrosamines for confirmation by reference standards, including three previously uncharacterized species: N-nitroso-tert-butylphenylamine, N-nitroso-2-pyrrolidinmethanol, and N-nitrosodesloratadine, although they only served as minor components of TONO. Overall, our study establishes an adaptable methodological framework for advancing the quantitative and qualitative analysis of specific and unknown components of TONO across water treatment and reuse scenarios.

Detection of serum CC16 by a rapid and ultrasensitive magnetic chemiluminescence immunoassay for lung disease diagnosis.

OBJECTIVES: It has been reported that serum Clara cell secreted protein 16 (CC16) is a potential biomarker for lung injury diseases, but currently, there is no other method that is faster, more accurate, or more sensitive being applied in clinical practice apart from ELISA. The current study was designed to established a magnetic nanoparticles chemiluminescence immunoassay (MNPs-CLIA) for highly sensitive automated detection of serum Clara cell secretory protein 16 (CC16), and validated its diagnostic performance for lung disease. METHODS: The study included the expression of CC16 recombinant protein, the preparation and screening of its monoclonal antibody (MAb), as well as the construction, optimization and analytical evaluation of the MNPs-CLIA method. The clinical application value of this method was investigated by detecting CC16 level in 296 serum samples. RESULTS: The linear range of the MNPs-CLIA assay system was 0.2-50 ng/mL, and the limit of detection was 0.037 ng/mL. Performance parameters such as specificity, recovery rate, and precision can meet the industry standards of in vitro diagnostic reagents. The established method reveals consistent results with ELISA (R2=0.9962) currently used clinically, and it also exhibits satisfactory diagnostic efficacy of silicosis, chronic obstructive pulmonary disease (COPD), and pulmonary sarcoidosis, with areas under the curve (AUC) of 0.9748, 0.8428 and 0.9128, respectively. CONCLUSIONS: Our established MNPs-CLIA method has the advantages of automation, high throughput, rapidity, and simplicity, and can be promoted for widely popularized in clinical applications. MNPs-CLIA detection of serum CC16 has efficient diagnostic potentiality for predicting and diagnosing lung diseases.

Evaluation of the analytical and clinical performance of a new high-sensitivity cardiac troponin I assay: hs-cTnI (CLIA) assay.

OBJECTIVES: Cardiac troponin (cTn) is the key biomarker for diagnosis of acute coronary syndrome (ACS). We performed a complete assessment of the high-sensitivity cardiac troponin I (hs-cTnI) (CLIA) assay on the analytical performance and clinical diagnostic performance, which was compared with Abbott ARCHITECT hs-cTnI assay. METHODS: Sex-specific 99th percentile upper reference limits (URLs) were determined from a healthy population of 424 males and 408 females. High-sensitivity performance was assessed by examining the imprecision at sex-specific URLs and the detectable results above LoD in a cohort of healthy population. The diagnostic performance of the hs-cTnI (CLIA) assay was validated in a population of 934 patients with suspected ACS. RESULTS: The 99th percentile URLs were 15.3 ng/L for female, 31.3 ng/L for male and 24.2 ng/L for overall population. The total imprecision near the sex-specific 99th percentile URLs were <5 %. 76.74 % of females, 97.12 % of males and 86.69 % of overall population had cTnI values exceeding the LoD, which met the criteria of high-sensitivity troponin assay. No cross-reactivity or interference was identified. The diagnostic sensitivity, specificity, PPV, NPV, and AUC of hs-cTnI (CLIA) assay were 97.97 , 90.70, 79.02, 99.21 % and 0.9885, respectively, which were comparable to ARCHITECT hs-cTnI assay. CONCLUSIONS: hs-cTnI (CLIA) assay is a high-sensitivity troponin I method with high precision, sensitivity and specificity. The clinical diagnostic performance of hs-cTnI (CLIA) is comparable to the established ARCHITECT hs-cTnI assay. Mindray's hs-cTnI (CLIA) assay is an attractive alternative for diagnosis of myocardial infarction with a high level of accuracy and safety.

Development of high-performance point-of-care aqueous VEGF detection system and proof-of-concept validation in RVO patients.

OBJECTIVES: To develop a sensitive point-of-care testing (POCT) aqueous vascular endothelial growth factor (VEGF) detection system, and assess its role for predicting the response to anti-VEGF treatment in macular edema secondary to retinal vein occlusion (RVO-ME) patients. METHODS: An automatic point-of-care aqueous humor Magnetic Particle Chemiluminescence Enzyme Immuno-Assay (MPCLEIA) VEGF detection system was developed. The predictive values of aqueous cytokine levels, in combination with imaging parameters, on anatomical treatment response (ATR, the relative central macular thickness change [ΔCMT/bl-CMT]) were analyzed. RESULTS: The automatic MPCLEIA system was able to provide results in 45 min with only 20 µL sample. Among the 57 eyes with available pre- and post-treatment evaluation, ATR significantly correlated with levels of interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1) and VEGF measured by Luminex xMAP platform, and VEGF measured by MPCLEIA. Optimal cut-off values for these biomarkers were 13.26 ng/L, 23.57 ng/L, 1,110.12 ng/L, 105.52 ng/L, and 85.39 ng/L, respectively. Univariate analysis showed significant associations between ATR category (good response if ATR≤-25 % or poor response otherwise) and IL-6, IL-8, MCP-1, VEGF-xMAP, and VEGF-MPCLEIA (p<0.05). Multivariate logistic regression revealed that ATR category was significantly associated with aqueous VEGF-MPCLEIA (p=0.006) and baseline(bl)-CMT (p=0.008). Receiver operating characteristics analysis yielded an AUC of 0.959 for the regression model combining VEGF-MPCLEIA and bl-CMT, for predicting ATR category. CONCLUSIONS: Our novel MPCLEIA-based automatic VEGF detection system enables accurate POCT of aqueous VEGF, which shows promise in predicting the treatment response of RVO-ME to anti-VEGF agents when combined with bl-CMT.

Nitrogen-Doped Carbon Dots Enhanced Hydrogen Carbonate-Hydrogen Peroxide Chemiluminescent Reaction and its Application in Ascorbic Acid Sensing.

Nitrogen-doped carbon dots (N-CDs) were prepared by self-exothermic procedure using grasshopper powder as a single precursor. The prepared N-CDs not only have excellent fluorescence properties, but also can catalyze and enhance the ultra-weak chemiluminescence of NaHCO3-H2O2. The reaction conditions of NaHCO3-H2O2-N-CDs CL were optimized. Under the optimal experimental conditions, when AA was added to the NaHCO3-H2O2-N-CDs CL system, AA had a significant inhibitory effect on the CL intensity of NaHCO3-H2O2-N-CDs. There was a good linear relationship between the calculated lg(I0/I) and the concentration of AA (C), and the calibration curve equation was lg(I0/I) = 0.03667 C-0.00708 (µM). The established CL analysis method has a detection limit of 0.12 µM for AA and a linear range of 0-50 µM. The selectivity of CL method was evaluated, and the method was successfully applied to the determination of AA in vegetable and fruit samples. The spiked recoveries were between 88.9% and 118.9%, which indicated that the method was simple, rapid, and sensitive, and had great potential in the determination of AA in foods.

A Novel Flow Injection Method with Chemiluminescence Detection for the Determination of Carmoisine in Gelatin Desserts.

Carmoisine dye, a red azo food colorant commonly utilized to impart a red color to synthetic food products, is the subject of this study. Here, we present a novel reversed flow injection analysis with a chemiluminescence detection (FIA-CL) method employing a newly developed homemade flow cell to determine carmoisine dye. This developed method is based on the inhibition effect of the dye on the chemiluminescence light (CL) emission generated from a luminal-hypochlorite system, whereby the reduction in CL intensity correlates directly with the concentration of carmoisine dye. Investigations into various analytical parameters were conducted to enhance method efficiency and applicability. A linear calibration graph of 4.0 to 100.0 µg mL-1 was established (R² = 0.9993), with a detection limit of LOD = 2.93 µg mL-1. Subsequent application of the proposed method to analyze gelatine dessert samples yielded results in reasonable agreement with those obtained using the reported HPLC method, as evidenced by student t-test and F-test analyses.

Chemiluminescence sensing for Hg2+ in environment water using carbon materials from PVC dechlorination as signal initiator.

Chemiluminescence (CL) sensing with good performance remains a challenge. The utilization of secondary residues from polyvinyl chloride (PVC) treatment is the key to improve PVC recycling rate. Herein, dechlorinated carbon materials from PVC/iron scrap co-treatment in subcritical water were used as CL sensing element. It was found that tiny changes in the spatial structure of aptamer could cause huge changes in CL signal of the residue-luminol system. A CL biosensor was constructed for mercury in environment water for the first time. The detection limit was estimated to be 0.37 pM. High sensitivity was mainly due to strong CL triggering and signal amplification from residues and effective regulating residue activity by aptamer space dimension. For real water samples, the results by residue CL analysis were consistent with that by cold vapor atom adsorption spectroscopy (CVAAS). Most strikingly, the used material was secondary residues from the treatment of PVC waste, which reduced the time and energy consumption of CL sensing. This research proposed the approach for routine monitoring mercury in environment but also provided the reference for developing other environmentally beneficial analysis platforms.

Iridium(III) solvent complex-based electrogenerated chemiluminescence method for the detection of 3-methylhistidine in urine.

3-Methylhistidine (3-MeHis) is increasingly used as an indicator of muscle protein breakdown. The development of a sensitive, simple, and non-invasive method for 3-MeHis assay is important in clinical practice. Herein, a sensitive, simple, and non-invasive electrogenerated chemiluminescence (ECL) method was proposed for the quantitation of 3-MeHis in urine by using an iridium(III) solvent complex ([Ir(dfppy)2(DMSO)Cl], dfppy = 2-(2,4-difluorophenyl)pyridine, Ir-DMSO) as a signal reagent. The photoluminescence (PL) and ECL responses of Ir-DMSO to 3-MeHis were studied. The ECL intensity of Ir-DMSO was enhanced in the presence of 3-MeHis because of the coordination recognition between Ir-DMSO and the imidazole group of 3-MeHis. Based on the enhancement of ECL intensity, 3-MeHis can be sensitively detected in the range of 5 to 25 µM. The detection limit was 0.4 µM. This is the first report of an ECL method for the quantitation of 3-MeHis. Further, to investigate the feasibility of the Ir-DMSO-based ECL method in practical applications, the developed ECL method was applied for 3-MeHis assay in urine samples of 28 healthy volunteers and 2 patients. The urine samples from patients hospitalized with obesity and kidney disease and healthy individuals were distinguished by the ECL responses of Ir-DMSO. The proposed ECL method based on the coordination recognition between iridium(III) solvent complex and the imidazole group of 3-MeHis allows inexpensive, fast, non-invasive, and sensitive detection of 3-MeHis in urine, which is promising for assessing large volumes of patients for routine analysis in clinical practices.

Electrogenerated chemiluminescence from luminol-labelled microbeads triggered by in situ generation of hydrogen peroxide.

We developed a sensing strategy that mimics the bead-based electrogenerated chemiluminescence immunoassay. However, instead of the most common metal complexes, such as Ru or Ir, the luminophore is luminol. The electrogenerated chemiluminescence of luminol was promoted by in situ electrochemical generation of hydrogen peroxide at a boron-doped diamond electrode. The electrochemical production of hydrogen peroxide was achieved in a carbonate solution by an oxidation reaction, while at the same time, microbeads labelled with luminol were deposited on the electrode surface. For the first time, we proved that was possible to obtain light emission from luminol without its direct oxidation at the electrode. This new emission mechanism is obtained at higher potentials than the usual luminol electrogenerated chemiluminescence at 0.3-0.5 V, in conjunction with hydrogen peroxide production on boron-doped diamond at around 2-2.5 V (vs Ag/AgCl).