Electrochemiluminescence Technology Research Articles

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.

Early Diagnosis of Triple-Negative Breast Cancer Based on Dual microRNA Detection Using a Well-Defined DNA Crown-Carbon Dots Structure as an Electrochemiluminescence Sensing Platform.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer (BC). Thus, early detection and accurate diagnosis of this cancer are crucial for improving the survival rate of patients. Specific microRNAs (miRNAs) have been implicated in the occurrence, proliferation, and metastasis of TNBC. Addressing this need, our study developed a biosensor platform for early and accurate TNBC diagnosis by integrating electrochemiluminescence (ECL) technology with a DNA sensing strategy. Specifically, synthesized positively charged carbon dots (CDs) were used to neutralize the electrostatic repulsion between DNA strands and facilitate the assembly of DNA triangular prisms (DNA TP-CDs). Hairpins were then incorporated into the DNA TP-CDs to form the final DNA crown structure. The early TNBC biomarker, microRNA-93-3p (miR-93-3p), allowed for the binding between the DNA Crown and the DNA track on the electrode and initiated the ECL signal. Subsequently, microRNA-210 (miR-210) unlocked the DNA tripedal walker, and its movement on the DNA Crown eventually quenched the ECL signal, enabling accurate TNBC diagnosis and tumor stage assessment. Our proposed biosensor had satisfactory sensing efficiency due to the ordered DNA track and rapid-moving DNA walker. The data revealed a good linear relationship between the ECL signals and the logarithm of miRNA concentrations, with miR-93-3p having a detection limit of 31.04 aM and miR-210 having a detection limit of 7.69 aM. The biosensor also showed satisfactory performance in serum samples and cells. Taken together, this study hopes to provide ideas and applications for clinical diagnosis as well as the personalized treatment of TNBC.

Protein denaturation inspired microchannel-based electrochemiluminescence sensor for formaldehyde detection

Establishing an effective system to measure formaldehyde (HCHO) content in food is of great significance due to food safety concern. Inspired by the mechanism of HCHO-induced protein denaturation and its effect on ion/molecule transport in nanochannels, a bioinspired microchannel-based electrochemiluminescence (ECL) sensor was constructed for HCHO detection. Benefiting from the water solubility of HCHO, the molecules rapidly spread and enriched at the ethylenediamine (EDA) functionalized microchannel interface. The reaction between EDA and HCHO significantly increased the negative charge density, leading to enhanced electroosmotic flow (EOF). This enhancement resulted in ion concentration depletion at the microchannel tip and a corresponding decrease in ionic current and ECL intensity. The ECL intensity exhibited a linear dependence on the logarithm of HCHO concentration ranging from 1 pg mL−1 to 100 ng mL−1, with a detection limit of 0.26 pg mL−1(S/N = 3). The biosensor demonstrated high selectivity, successfully detecting HCHO in shrimp samples. The performance of the bioinspired sensor was confirmed through comparation with existing methods, showcasing its superior sensitivity and reliability. The bioinspired sensor provides robust technical support for HCHO detection, crucial for food safety monitoring. Additionally, the innovative combination of bionics and microchannel-based ECL technology broadens the application range of ECL sensors, marking a significant advancement in the field.

Framework-Induced Electrochemiluminescence Enhancement of an AIEgen-Based MOF Coupled with Heterostructured TiO2@Ag NPs as an Efficient Coreaction Accelerator for Sensitive Biosensing.

In conventional metal-organic framework (MOF) luminophore-involved electrochemiluminescence (ECL) systems, the aggregation-caused quenching commonly exists for the organic luminescent ligands, limiting the ECL efficiency and detection sensitivity. Herein, by employing the aggregation-induced emission luminogen (AIEgen) 1,1,2,2-tetra(4-carboxylbiphenyl)ethylene (H4TCBPE) as a ligand, one high-efficiency ECL emitter (Zr-MOF) was synthesized through a simple hydrothermal reaction. Compared with H4TCBPE monomers and their aggregates, the resultant Zr-MOF possesses the strongest ECL emission, which is mainly attributed to the framework-induced ECL enhancement. Specifically, the heterostructure was prepared by the deposition of silver nanoparticles on TiO2 microflowers and utilized as an efficient coreaction accelerator. Remarkably, the formative heterojunction can increase the interfacial charge transfer efficiency and promote the carrier separation, facilitating the oxidation of coreactant tripropylamine. In this way, a novel aptamer-mediated ECL sensing platform is constructed, achieving the sensitive analysis of adenosine triphosphate with a low detection limit of 0.17 nM. As a proof-of-concept study, this work may enlighten the rational design of new-type MOF-based ECL materials and expand the application scope of the ECL technology.

Coreactant-free aggregation-induced electrochemiluminescence system based on the novel zinc-luminol metal-organic gel for ultrasensitive detection of PiRNA-823

Aggregation-induced electrochemiluminescence (AIECL) technology has aroused widespread interest due to the significant improve in ECL response by solving the problems of aggregation-caused quenching and poor water solubility of the luminophore. However, the existing AIECL emitters still suffer from low ECL efficiency, additional coreactants and complex synthesis steps, which greatly limit their applications. Herein, luminol, as a kind of AIE molecule, was assembled with Zn2+ nodes to obtain a novel microflower-like Zinc-luminol metal-organic gel (Zn-MOG) by one-step method. In the light of the strong affinity of N atoms in luminol ligand to Zn2+, Zn-MOG with vigorous viscosity and stability can be formed immediately after vortex oscillation, overcoming the main difficulties of the complicated synthesis steps and poor film-forming performance encountered in current AIECL materials. Impressively, an AIECL resonance energy transfer (RET) biosensor was constructed using Zn-MOG as a donor and Alexa Fluor 430 as an acceptor in combination with DNA-Fuel-driven target recycling amplification for the ultrasensitive detection of PiRNA-823. The fabricated biosensor exhibited a wide linear relationship in the range of 100 aM to 100 pM and a detection limit as low as 60.0 aM. This work is the first to realize the construction of ECL emitters using the AIE effect of luminol, which provides inspiration for the design of AIECL systems without adding coreactants.

Multimetal-Based Metal-Organic Framework System for the Sensitive Detection of Heart-Type Fatty Acid Binding Protein in Electrochemiluminescence Immunoassay.

In this work, an electrochemiluminescence (ECL) quenching system using multimetal-organic frameworks (MMOFs) was proposed for the sensitive and specific detection of heart-type fatty acid-binding protein (H-FABP), a marker of acute myocardial infarction (AMI). Bimetallic MOFs containing Ru and Mn as metal centers were synthesized via a one-step hydrothermal method, yielding RuMn MOFs as the ECL emitter. The RuMn MOFs not only possessed the strong ECL performance of Ru(bpy)32+ but also maintained high porosity and original metal active sites characteristic of MOFs. Moreover, under the synergistic effect of MOFs and Ru(bpy)32+, RuMn MOFs have more efficient and stable ECL emission. The trimetal-based MOF (FePtRh MOF) was used as the ECL quencher because of the electron transfer between FePtRh MOFs and RuMn MOFs. In addition, active intramolecular electron transfer from Pt to Fe or Rh atoms also occurred in FePtRh MOFs, which could promote intermolecular electron transfer and improve electron transfer efficiency to enhance the quenching efficiency. The proposed ECL immunosensor demonstrated a wide dynamic range and a low detection limit of 0.01-100 ng mL-1 and 6.8 pg mL-1, respectively, under optimal conditions. The ECL quenching system also presented good specificity, stability, and reproducibility. Therefore, an alternative method for H-FABP detection in clinical diagnosis was provided by this study, highlighting the potential of MMOFs in advancing ECL technology.

Association of inflammatory cytokines expression in cerebrospinal fluid with the severity and prognosis of spontaneous intracerebral hemorrhage

ObjectiveTo investigate the potential diagnostic and prognostic implications of inflammatory cytokine levels in the cerebrospinal fluid (CSF) of patients with spontaneous intracerebral hemorrhage (SICH) upon their initial hospital admission.MethodsOur cohort included 100 patients diagnosed with acute SICH, presenting to the Department of Neurosurgery. Additionally, we recruited 50 individuals without central nervous system (CNS) pathology, treated concurrently at our facility, as controls. CSF samples, collected upon hospital entry, were quantitatively assessed for 10 inflammatory cytokines using the Mesoscale Discovery Platform (MSD, Rockville, MD, USA) electrochemiluminescence technology, followed by validation through enzyme-linked immunosorbent assay (ELISA).ResultsWe observed a marked elevation of IL-6, IL-8, IL-10, and TNF-α in the CSF of the SICH subgroup compared to controls. Higher Glasgow Coma Scale (GCS) scores in SICH patients corresponded with lower CSF concentrations of IL-6, IL-8, IL-10, and TNF-α, indicating an inverse relationship. Notably, CSF inflammatory cytokine levels were consistently higher in SICH patients with hydrocephalus than in those without. Increases in IL-6, IL-8, IL-10, and TNF-α in the CSF were notably more pronounced in the poor prognosis group (Glasgow Outcome Scale, GOS 1–3) compared to those with a favorable prognosis (GOS 4–5). The AUC values for these cytokines in predicting SICH prognosis were 0.750, 0.728, 0.717, and 0.743, respectively.ConclusionsInitial CSF levels of IL-6, IL-8, IL-10, and TNF-α upon admission provide significant insights into the severity of neural damage and are robust indicators for prognosis in SICH patients.

Comorbidities Incorporated to Improve Prediction for Prevalent Mild Cognitive Impairment and Alzheimer's Disease in the HABS-HD Study.

Blood biomarkers have the potential to transform Alzheimer's disease (AD) diagnosis and monitoring, yet their integration with common medical comorbidities remains insufficiently explored. This study aims to enhance blood biomarkers' sensitivity, specificity, and predictive performance by incorporating comorbidities. We assess this integration's efficacy in diagnostic classification using machine learning, hypothesizing that it can identify a confident set of predictive features. We analyzed data from 1,705 participants in the Health and Aging Brain Study-Health Disparities, including 116 AD patients, 261 with mild cognitive impairment, and 1,328 cognitively normal controls. Blood samples were assayed using electrochemiluminescence and single molecule array technology, alongside comorbidity data gathered through clinical interviews and medical records. We visually explored blood biomarker and comorbidity characteristics, developed a Feature Importance and SVM-based Leave-One-Out Recursive Feature Elimination (FI-SVM-RFE-LOO) method to optimize feature selection, and compared four models: Biomarker Only, Comorbidity Only, Biomarker and Comorbidity, and Feature-Selected Biomarker and Comorbidity. The combination model incorporating 17 blood biomarkers and 12 comorbidity variables outperformed single-modal models, with NPV12 at 92.78%, AUC at 67.59%, and Sensitivity at 65.70%. Feature selection led to 22 chosen features, resulting in the highest performance, with NPV12 at 93.76%, AUC at 69.22%, and Sensitivity at 70.69%. Additionally, interpretative machine learning highlighted factors contributing to improved prediction performance. In conclusion, combining feature-selected biomarkers and comorbidities enhances prediction performance, while feature selection optimizes their integration. These findings hold promise for understanding AD pathophysiology and advancing preventive treatments.

Simultaneous detection of Alzheimer's biomarkers using a visual electrochemiluminescence bipolar array

Alzheimer's disease (AD), a progressive neurological disorder, presents challenges in early detection due to the limitations and costs of neuropsychological tests and neuroimaging. This study introduces a visual electrochemiluminescence (ECL) sensing device employing red and green signal lights on dual-channel closed bipolar electrodes (BPEs) for simultaneous Aβ oligomers and Tau proteins detection. To mitigate cross-chemical reactions, we physically separated target detection and ECL production within different chambers connected by BPEs. Utilizing efficient gold clusters (Au NCs) and Ru(bpy)32+ as green and red emitters, respectively, along with methylene blue (MB) as the recognition probe on the cathode sensing platform, we achieved a detection limit of 2.6 pM for Aβ oligomers and 0.3 pM for Tau proteins by measuring visual ECL intensity at two anodic poles of BPEs. This approach minimizes cross-chemical reactions, ensures robust ECL signal sensors, and allows integration of multiple sensors on a single chip. The proposed portable bipolar electrode chips employing ECL technology show promise for early and precise Alzheimer's disease diagnosis and personal healthcare.

Effect of fsh on lipid profile in postmenopausal women

The World Health Organization (WHO) and Stages of Reproductive Aging Workshop (STRAW) define menopause as a permanent endpoint of the menstrual cycle for one year that occurs naturally or by induction of surgical procedure, chemotherapy or radiation .The etiology of menopause is classified into physiological and non-physiological. Pathophysiology of menopause includes the decline of ovary function in menopause, response to a loss of ovarian feedback mechanism, and the decline of the hypothalamus and pituitary function. Endocrine changes in menopause lead to alteration of gonadotropin secretion cycle patterns, changes in steroid and peptide hormones through monophasic patterns to increase gonadotropin, and decreased estrogen .Aim: This study aims to investigate the effect of FSH on lipid profile in postmenopausal women. Study design: A cross-section observational study. Method: The study is a cross-sectional study done on 90 women. These women aged more than 50 years had cessation of menstrual cycle for over a year. The blood samples were taken from 90 postmenopausal women, and interviews were conducted using a questionnaire. FSH measure, by ElectroChemiLuminescence (ECL) technology for immunoassay analysis done by Cobas e411 device. Lipid profile measure, by manual techniques done by use of spectrophotometer device. Result: We observed increase in Follicle-stimulating hormone (FSH) during postmenopause has a positive significant correlation with body mass index (BMI) (r 0.350, p 0.001), total cholesterol (TC) (r 0.397, p 0.001) and Low-density lipoprotein (LDL) ( r 0.421, p 0.001) FSH also correlated positively but insignificant correlation with triglyceride (TG) (r 0.175, p 0.098) and very low-density lipoproteins (VLDL) ( r 0.055, p 0.604). FHS has a negative significant correlation with Estradiol ( r -0.509, p 0.001) and Vit.D( r-0.220, p 0.037) as well as FSH correlated negative but insignificant with age ( r -0.142, p 0.183) and High-density lipoprotein (HDL) (r -0.048, p 0.656). Conclusion: The current study showed a significant positive correlation of FSH with TC and LDL, an insignificant positive correlation with TG, and an insignificant negative correlation with HDL. Keywords: Postmenopause, FSH, Lituenizing Hormone, HDL

Ultrasensitive analysis of miRNA-141 based on coordination-mediated lamellar nanostructures of [-TPE-(COOH)4-Al-]nLNs with highly efficient aggregation-induced electrochemiluminescence

In this work, [-TPE-(COOH)4-Al-]nLNs with lamellar nanostructures (LNs) were conveniently synthesized through the high affinity coordination between Al3+ and carboxyl groups of 1,1,2,2-tetra(4-carboxylphenyl)ethylene (TPE-(COOH)4). As there was a strong chelate effect and π-π stacking, the [-TPE-(COOH)4-Al-]nLNs could extend not only on a flat surface, but also in a spatial stack. The obtained [-TPE-(COOH)4-Al-]nLNs exhibited excellent aggregation-induced electrochemiluminescence (AIECL) which was much stronger than that of the TPE-(COOH)4 monomer. Furthermore, through stacking and adjustment of Al3+, they also possessed higher electrochemiluminescence (ECL) efficiency compared to the crystal structure based on TPE-(COOH)4, which has a denser aggregation structure that causes aggregation-caused quenching (ACQ) phenomenon. Meanwhile, the [-TPE-(COOH)4-Al-]nLNs with Al3+ as the coordination center were superior to the coordination aggregation structures with heavy metal or rare metal ions as the coordination centers in terms of cost and biocompatibility. Using [-TPE-(COOH)4-Al-]nLNs as a luminescent material, an ultrasensitive ECL biosensor was fabricated for miRNA-141 detection combined with the cascaded strand displacement amplification (CSDA) strategy. Compared to traditional strand displacement amplification (SDA) reaction, the output DNA usually obtained in the first cycle could further return to attend multiple cycle amplification, resulting in the generation of more output DNA and an obvious signal amplification. The constructed biosensor showed excellent detection performance with a linear range from 1 × 10-18 M to 1 × 10-9 M and a detection limit of 1.2 × 10-19 M. This study provided a more convenient and effective AIECL strategy for tetraphenylethylene (TPE) derivatives and broadened the application of ECL technology in ultra-sensitive biochemical detection.

Guest Molecular Assembly Strategy in Covalent Organic Frameworks for Electrochemiluminescence Sensing of Uranyl

The application of covalent organic frameworks (COFs) in electrochemiluminescence (ECL) is promising in environmental monitoring. Developing an emerging design strategy to expand the class of COF-based ECL luminophores is highly desirable. Here, a COF-based host-guest system was constructed through guest molecular assembly to deal with nuclear contamination analysis. The efficient charge transport network was formed by inserting an electron-withdrawing guest tetracyanoquinodimethane (TCNQ) into the open space of the COF host (TP-TBDA; TP = 2,4,6-trihydroxy-1,3,5-benzenetricarbaldehyde and TBDA = 2,5-di(thiophen-2-yl)benzene-1,4-diamine) with an electron-donating property; the construction of the COF-based host-guest system (TP-TBDA@TCNQ) triggered the ECL emission of non-emitting TP-TBDA. Furthermore, the dense active sites in TP-TBDA were utilized to capture the target substance UO22+. The presence of UO22+ broke the charge-transfer effect in TP-TBDA@TCNQ, resulting in the weakening of the ECL signal, thus the established ECL system integrating the low detection limit with high selectivity monitors UO22+. This COF-based host-guest system provides a novel material platform for constructing late-model ECL luminophores and creates an opportunity for the vigorous ECL technology.

Controlled Growth of MoS2 on Dendritic Ferric Oxide to Enhance Electrochemiluminescence of Nitrogen-Doped Carbon Quantum Dots for Sensitive Immunoassay.

The essential expansion of electrochemiluminescence (ECL) technology into clinical detection relies on sensitive and stable signal and maintenance of the activity of the immune molecules during the analysis. This poses a critical challenge for an ECL biosensor as a luminophore in general requires high potential excitation resulting in a strong ECL signal; nevertheless, it has an irreversible effect on the activity of the antigen or antibody. Herein, a novel electrochemiluminescence (ECL) biosensor utilizing nitrogen-doped carbon quantum dots (N-CQDs) as emitters and molybdenum sulfide/ferric oxide (MoS2@Fe2O3) nanocomposites as a coreaction accelerator was developed for detection of neuron-specific enolase (NSE), a biomarker of small cell lung cancer. The doping of nitrogen allows the CQDs to exhibit ECL signals with low excitation potential, with a more viable activity possible for immune molecules. MoS2@Fe2O3 nanocomposites exhibit superior coreaction acceleration characteristics in hydrogen peroxide than any single component of them, and the highly branched dendrite microstructure provides a large number of binding sites for immune molecular, which is an inevitable factor for trace detection. In addition, ion beam sputtering gold particle technology is introduced into the sensor fabrication via an Au-N bond, which will provide sufficient density orientation for capturing the antibody load via the Au-N bonds. With excellent repeatability, stability, and specificity, the as-purposed sensing platform showed differentiated ECL responses of NSE range from 10.00 fg/mL to 500 ng/mL, and the limit of detection (LOD) was calculated of 6.30 fg/mL (S/N = 3). The proposed biosensor is prospective to provide a new avenue for the analysis of NSE or other biomarkers.

Enhanced electrochemiluminescence immunoassay: 2. Enabling signal detection at an early stage of incubation for rapid point-of-care testing

Signal detection in a label-based immunoassay is performed normally when the antigen/antibody binding reaction reaches the equilibrium state during the incubation period of an assay process. Shortening the incubation period in an assay helps reduce the turnaround time and is particularly valuable for point-of-care testing, but the cost is the reduction of signal level and, possibly, measurement precision as well. This work demonstrates that the signal loss could be offset by the stronger emission of an electronically neutral ruthenium(II) complex label, Ru(2, 2′-bipyridine) (bathophenanthroline disulfonate)[4-(2, 2′-bipyridin-4-yl)butanoic acid], used in the electrochemiluminescence (ECL) immunoassay. Combined with the uniquely well-established flow-through washing process in the automated ECL analyzers and the precise control over liquid handling, the assays performed with a 5-minute incubation period showed the same signal level and measurement precision as those of conventional ECL assays. Additionally, the absence of biotin and streptavidin components in the reagent formulation avoids the biotin-streptavidin interaction during assay incubation and fundamentally eliminates the interference of biotin, especially when used in some high-dose therapies. The results obtained from the procalcitonin prototype kit and the supporting evidence from other preliminary reagents (for SARS-CoV-2 N protein and troponin T) are general. The nonequilibrium detection, along with the downsized instrument design, makes the enhanced ECL (EECL) technology a fast high-performance POCT platform that provides the same high-quality data as those generated from the widely deployed [Ru(bpy)3]2+based laboratorial ECL systems.The anticipated regulatory approval and follow-up clinical implementation will beasignificant stride in the decade-long pursuit of novel ECL labels.

Dual-quenching mechanisms in electrochemiluminescence immunoassay based on zinc-based MOFs of ruthenium hybrid for D-dimer detection

The successful application of electrochemiluminescence (ECL) in immunoassay for clinical diagnosis requires improving sensitivity and accuracy. Herein was reported an ECL analytical model based zinc-based metal-organic frameworks of ruthenium hybrid (RuZn MOFs) as the signal emitter. To enlarge the output difference, the quenching effect of three different noble metal nanoparticles included palladium seeds (Pdseeds), palladium octahedrons (Pdoct), and Pt-based palladium (Pd@Ptoct) core-shell were researched. Among them, Pd@Ptoct core-shell possessed higher activity and improved durability than Pd-only (NPs), they could load more protein macromolecules amicably and stabilized in the analysis system. Furthermore, since the charge redistribution owing to the hybridization of the Pt and Pd atoms in Pd@Ptoct, it could generate the electron flow maximumly from the emitter RuZn MOFs to Pd@Ptoct and result in the enhancement of quenching ECL. And the UV absorption of noble metal nanoparticles overlapped with the ECL emission of RuZn MOFs to varying degrees, which caused the behavior of resonance energy transfer (RET) reaction at the same time. This would greatly promote the sensitivity of this ECL system compared with the traditional single quenching mechanism. Based on this, a signal-off immunsensor was constructed to sensitive detection of D-dimer with linearity range from 0.001 to 200 ng mL−1, limit of detection (LOD) was 0.20 pg mL−1 and provide a further theoretical basis for the clinical application of ECL technology.

312. Performance and validation of an adaptable multiplex assay for detection of serologic response to SARS-CoV-2 infection or vaccination.

Abstract Background A wide array of assays to detect the serologic response to SARS-CoV-2 have been developed since the emergence of the pandemic. The majority of these are either qualitative or semi-quantitative, detect antibodies against one antigenic target, and are not adaptable to new antigens. Methods We developed a new, multiplex immunoassay to detect antibodies against the receptor binding domain, S1 and S2 spike subunits and nucleocapsid (N) antigens of SARS-CoV-2 (the CEPHR SARS-CoV-2 Serology Assay). This assay uses electrochemiluminescence technology which allows for a broad dynamic range, and a linker format which allows for the addition of new antigenic targets. We tested this assay on a series of biobanked samples and validated its performance against the Abbott SARS-CoV-2 IgG and Abbott SARS-CoV-2 IgG II assays, and the MesoScale Diagnostics V-PLEX SARS-CoV-2 Panel 2 Kit. Results Participant demographics are shown in Table 1. The mean (standard deviation (SD)) intra-assay (within plate) coefficient of variation (CV) of 80 plasma samples run on the same plate was 3.9% (2.9) for N, 3.8% (6.2) for RBD, 3.8% (5.9) for S1 and 3.9% (5.3) for S2. The mean (SD) inter-assay CV derived from 5 samples run across 3 days by two different operators was 11% (6.5) for N, 13% (5.7) for RBD, 14% (8.9) for S1 and 13% (5.1) for S2. In the convalescent group (n=193), overall sensitivity for each assay was; RBD 82% (95% CI 76-87), S1 86% (81-91%), S2 88% (83 – 92%) and N 72% (64 – 78%). Sensitivity improved when analysis included only individuals who were sampled more than 14 days from onset of symptoms (n=166), RBD 87% (81 – 95%), S1 91% (85 – 95%), S2 91% (85 – 95%) but not for the N-target (73% (66-80%)). In vaccinated individuals (n = 58), 100% (94-100%) had both detectable RBD and S1 antibodies. Overall specificity was 96% (87-99%) for RBD, 90% (78-97%) for S1, 94% (84-99%) for S2 and 90% (78-97%) for N. There was excellent correlation between the Abbott IgG II and both CEPHR anti-RBD IgG (rho 0.91) and CEPHR anti-S1 IgG (rho 0.9, both p < 0.001, Figure 1.) and the V-PLEX full spike and both CEPHR RBD IgG (rho 0.83) and S1 IgG (rho 0.82, both p < 0.001, Figure 4). Table 1Participant demographics Correlation between CEPHR RBD, Abbott SARS-CoV-2 IgG II anti spike assay and V-PLEX Spike assay. Vertical dashed line represents CEPHR RBD positivity threshold, horizontal dashed line indicates Abbott positivity threshold. B: Correlation between CEPHR RBD and MSD V-PLEX Spike IgG. Vertical dashed line represents CEPHR RBD positivity threshold, no positivity threshold provided by MSD. Conclusion The CEPHR SARS-CoV-2 Serology Assay is a robust, customisable, multiplex serologic assay for the detection of several different IgG specific to SARS-CoV-2. Disclosures All Authors: No reported disclosures.

Significantly enhanced electrochemiluminescence of nalidixic acid/S2O82− system by isonicotinic as Co-reaction accelerator for ultrasensitive detection of tetraethylenepentamine

• A novel ECL system consisting of nalidixic acid (NA) and K 2 S 2 O 8 was investigated. • 4-Pyridinecarbohydrazide as a co-reactant accelerator that significantly amplifies the ECL signal of the NA system. • A tetraethylenepentamine detection strategy based on ECL technology was developed. This work presents a method for the establishment of a highly sensitive and selective nalidixic acid and S 2 O 8 2- (NA/S 2 O 8 2- ) electrochemiluminescence (ECL) system using isonicotinic (INH) as a co-reaction accelerator. After optimizing the experimental conditions including scan rate, pH value of buffer solution, concentration, etc., the chemiluminescence mechanism of the system was studied in detail using fluorescence spectroscopy, ECL spectroscopy and cyclic voltammetry (CV). The results show that INH is an efficient co-reaction accelerator, which interacts with the co-reactant S 2 O 8 2- but not the luminophore NA to promote the production of more oxidant SO 4 ·– , which then further reacts with NA to generate excited state species NA * with strong ECL signal, indicating that co-reaction accelerators can provide a simple, efficient, and low-cost method for signal amplification. Based on the great ECL enhancement of INH for the NA/S 2 O 8 2- system, under the optimal experimental conditions, highly sensitive and selective electrochemiluminescence detection of tetraethylenepentamine (TEPA) was achieved.

Ratiometric ECL sensor based on Apt-AuNS@Lu nanoprobe for analyzing cell swelling-induced ATP release.

A novel ratiometric electrochemiluminescence (ECL) system based on gold nanostars (AuNSs) support was constructed for the determination of hypotonicity-induced ATP release from HepG2 cells. AuNS@Lu nanoprobe was used as anodic luminophore and K2S2O8 as cathodic luminophore as well as anodic co-reactant. AuNS with the large specific surface was adopted to adsorb plentiful luminol to form solid-state probe and as affinity support to immobilize ATP aptamer (Apt). The obtained nanocomposite (Apt-AuNS@Lu) generated astrong ECL signal at + 0.4V (vs. Ag/AgCl) with co-reactant K2S2O8, because of excellent conductivity and catalytic activity of AuNS. Furthermore, graphene oxide was reduced onto indium tin oxide (ITO) electrodes to facilitate the electron transfer. Following, polydopamine (PDA) film was formed via self-polymerization, improving stability and adhesion of the electrode surface. To immobilize ATP capture aptamer (AptC), abounding AuNSs were attached to RGO/PDA surface. When the sensor was incubated in the mixture solution of Apt-AuNS@Lu and target ATP, the ECL signal of Apt-AuNS@Lu increased with the increase of ATP concentration, meanwhile, the signal of K2S2O8 declined. The ratio of the two luminophores was used for the quantitative determination of ATP. The linear range was 5 to 250nM, and the limit of detection was 1.4nM at (3σ)/S. The method was successfully applied to analyze ATP release from HepG2 cells stimulated by 0.45% NaCl hypotonic solution. The results showed that the release kinetics profile of ATP had a sigmoidal shape with rapid release within 10min and then slowed. Compared to the isotonic groups, the intracellular ATP concentration was 3.7 ± 0.3µM (n = 3) decreasing by 40.3% and the extracellular was 23.4 ± 1.2nM (n = 3) increasing by 9.2 times in the hypotonicity for 10min, which showed ATP release from cells and good agreement with commercial ELISA test. The proposed strategy would be beneficial to broadening application of ECL technology in studying cell biological functions.

USE OF ELECTROCHEMILUMINESCENCE METHODS TO EVALUATE THE RELATIONSHIP BETWEEN OVARIAN RESPONSE AND ANTI-MULLERIAN HORMONE (AMH) LEVELS WHEN THEY ARE LOWER THAN 1 NG/ML

The evolution of biochemical methods to measure AMH allowed to obtain increasingly precise and reliable values of this marker of ovarian reserve. The Elecsys® AMH assay is an ELISA-type immunoassay based on electrochemiluminescence (EQL) technology and represents one of the most robust diagnostic methods for measuring this hormone. Elecsys® AMH assay could allow the analysis of the relationship between the number of oocytes obtained in a follicular puncture after controlled ovarian stimulation (COS) with AMH levels, when they are lower than 1 ng/ml, a value below which the ovarian response could not be predicted with sufficient confidence. We aimed to establish the diagnostic sensitivity of the Elecsys°AMH method when the hormone level is less than 1 ng/ml in relation to the number of oocytes recovered in follicular punctures. Specifically, determine if there are differences in the number of oocytes obtained depending on the concentration of AMH in the sample: less than 0.49 ng/ml and between 0.50 – 0.99 ng/ml

Investigation of Some Factors Affecting Homocysteine Levels

Amaç: Bu çalışmada, yaş, cinsiyet, kanser ve sedanter yaşam gibi bazı faktörlerin homosistein düzeyleri üzerine olan etkisinin incelenmesi amaçlanmıştır.Yöntem: Çalışmaya, yaşları üç ile 93 arasında değişen 266 kişi dahil edildi. Bu 266 kişiden 109'u erkek, 157'si kadındır. Ayrıca 266 kişiden 120'si sedanter yaşam süren yatalak hasta ve 146'sı sağlıklı bireydir. Bu 120 hastanın 78'i kanser tanısı alan hasta, diğerleri kanser tanısı olmayan hastalardan oluşmaktadır. Homosistein analizi, elektrokemilüminesans teknolojisi kullanılarak Cobas®8000 analizörünün immünokimya modülünde yapılmıştır. Homosistein düzeyleri ile yaş arasındaki ilişkiyi görmek için korelasyon analizi yapılmıştır. Cinsiyet, kanser ve sedanter yaşam faktörlerinin etkisi Mann-Whitney U testi ile yapılmıştır.Bulgular: Çalışmaya dahil edilen bireylerin homosistein düzeyleri ile yaşları arasında pozitif korelasyon saptandı (r=0.610, p<0.001). Erkek sağlıklı bireylerin homosistein düzeyleri, kadın sağlıklı bireylerin homosistein düzeylerinden anlamlı olarak daha yüksek saptandı (p=0.001). Kanser tanısı alan hastaların homosistein düzeyleri, kanser tanısı almayan bireylerin homosistein düzeylerinden anlamlı olarak daha yüksek saptandı (p<0.001). Yatalak hastaların homosistein düzeyleri, yatağa bağımlı olmayanların homosistein düzeylerinden anlamlı olarak daha yüksek saptandı (p<0.001).Sonuç: Hemşirelerin Sonuç olarak, yaş, cinsiyet, kanser ve sedanter yaşamın homosistein düzeylerine etkisi saptanmıştır. Ayrıca, kanser tanısı olan hastalarda ve sedanter yaşam süren hastalarda hiperhomosisteinemi gözlenmiştir.