Chemiluminescence Detection System Research Articles

Automated magnetic-bead-assisted sequential extraction technology for simultaneous detection of Aβ1-42 and Aβ1-40 in cerebrospinal fluid: An advance toward fully automated liquid chromatography-tandem mass spectrometry method

Traditional solid-phase extraction (SPE) LC–MS/MS is limited by high costs, turnaround times, and procedural complexity, which limited the usage in clinical practice. This study aimed to establish a robust UPLC–MS/MS method with automated magnetic-bead-assisted sequential extraction (MBASE) technology to simultaneously measure Aβ1-42 and Aβ1-40 in cerebrospinal fluid (CSF). A Waters TQ-XS triple quadrupole mass spectrometer and Acquity UPLC Protein BEH C4 column were used. The targeted analytes were extracted and concentrated using the automated MBASE technology with chemically modified magnetic MCX beads. Analytical performance was verified referring to the CLSI C62-A and EP-15-A3 guidelines. A total of 68 CSF samples were collected and analyzed using the MBASE UPLC–MS/MS method, traditional SPE UPLC–MS/MS method, and Lumipulse G fully automated chemiluminescence detection system, and method comparison analysis is conducted. The MBASE UHPLC–MS/MS method showed an analytical performance equivalent to that of traditional SPE technology, with a higher sample throughput and smaller amount of materials ($34.98 vs. $493.96) and labor cost (101 min vs. 140 min) for 96 samples. The limit of quantification (LOQ) of Aβ1-42 and Aβ1-40 was 0.10 ng/mL and 0.05 ng/mL; recovery was 88.35–107.07 % and 95.72–96.60 %; and total imprecision was 3.69–6.83 % and 3.02–3.61 %, respectively. The measurements were faithfully reproduced within the allowable levels of uncertainty using certified reference materials. The correlations between this MBASE UPLC–MS/MS method, the SPE UPLC–MS/MS method, and Lumipulse G fully automated biochemical analysis method are all deemed good (r = 0.869–0.936), and the MBASE- and SPE-UPLC–MS/MS methods showed comparable measurements. To our knowledge, our study firstly verified the robust performance of the MBASE UPLC–MS/MS method to simultaneously determine Aβ1-42 and Aβ1-40 in CSF. With further introduce of automation, the assay with high accuracy and low material and labor costs will become a promising clinical technology.

Urinary Free Cortisol Determination and Interferences Studies Using Liquid Chromatography Coupled to Tandem Mass Spectrometry after On-Line Solid Phase Extraction Based on TurboflowTM Chromatography.

(1) A 24 h urinary free cortisol (UFF) is one of the first-line exams recommended for the diagnosis of Cushing's syndrome. In a hospital hormonology department, this activity can exceed several hundred dosages per week. The UFF is generally determined via an immunoassay with an automate using a chemiluminescence or electrochemiluminescence detection system. To increase the cortisol concentration in the analyzed sample, the automated analysis is preceded by urine extraction, which does not prevent there from being some interferences due to other steroids with close structures. (2) This paper describes the development of on-line solid phase extraction coupled to liquid chromatography and mass spectrometry for the analysis of urinary free cortisol. The on-line extraction was based on the TurboflowTM chromatography coupled to the analytical column by two valves, easily available for the laboratories. (3) The choice of the Accucore Polar Premium® analytical column made it possible to avoid analytical interferences with exogenous or endogenous molecules having the same SRM transition (363 → 121) as cortisol. (4) The method was fully validated in the range of clinically relevant concentrations from the lower limit of quantification (LLOQ) to 411.75 nmol·L-1.

RETRACTED: Development of a highly sensitive chemiluminescence immunoassay using a novel signal-enhanced detection system for quantitation of durvalumab, an immune-checkpoint inhibitor monoclonal antibody used for immunotherapy of lung cancer

Durvalumab (DUR) is a human monoclonal antibody used for the immunotherapy of lung cancer. It is a novel immune-checkpoint inhibitor, which blocks the programmed death 1 (PD-1) and programmed death-ligand 1 (PD-L1) proteins and works to promote the normal immune responses that attack the tumour cells. To support the pharmacokinetic (PK) studies, therapeutic drug monitoring (TDM) and refining the safety profile of DUR, an efficient assay is required, preferably immunoassay. This study describes, for the first time, the development of a highly sensitive chemiluminescence immunoassay (CLIA) for the quantitation of DUR in plasma samples with enhanced chemiluminescence detection system. The CLIA protocol was conducted in 96-microwell plates and involved the non-competitive binding reaction of DUR to its specific antigen (PD-L1 protein). The immune complex of DUR with PD-L1 formed onto the inner surface of the assay plate wells was quantified by a chemiluminescence (CL)-producing horseradish peroxidase (HRP) reaction. The reaction employed 4-(1,2,4-triazol-1-yl)phenol (TRP) as an efficient enhancer of the HRP-luminol-hydrogen peroxide (H2O2) CL reaction. The optimum protocol of the proposed CLIA was established, and its validation parameters were assessed as per the guidelines for the validation of immunoassays for bioanalysis. The working dynamic range of the assay was 10-800pgmL-1 with a limit of detection (LOD) of 10.3pgmL-1. The assay enables the accurate and precise quantitation of DUR in human plasma at a concentration as low as 30.8pgmL-1. The CLIA protocol is simple and convenient; an analyst can analyse several hundreds of samples per working day. This high throughput property enables the processing of many samples in clinical settings. The proposed CLIA has a significant benefit in the quantitation of DUR in clinical settings for assessment of its PK, TDM and refining the safety profile.

Validation of N-LightTM L. monocytogenes for Detection of Listeria monocytogenes on Environmental Surfaces: AOAC Performance Tested MethodSM 122002.

The NEMIS Technologies N-LightTM L. monocytogenes assay uses chemiluminescence designed for the qualitative detection of Listeria monocytogenes from environmental surface samples. To validate the NEMIS Technologies N-Light L. monocytogenes assay as part of the AOAC Performance Tested MethodSM program for the detection of L. monocytogenes on stainless steel, plastic (polystyrene), and ceramic environmental surfaces. Using the Vitl Life Science Solutions Lu-mini luminometer, the NEMIS Technologies N-Light L. monocytogenes assay was compared to the ISO 11290-1:2017: Microbiology of the Food Chain-Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. - Part 1 using a 1" × 1" stainless steel test area in an unpaired study design. The NEMIS Technologies N-Light L. monocytogenes assay using the Vitl Life Science Solutions Lu-mini luminometer demonstrated no statistically significant differences between presumptive and confirmed results or between candidate and reference method results. Data for additional Performance Tested MethodSM studies met acceptance criteria requirements. The NEMIS Technologies N-Light L. monocytogenes assay is an effective method for the qualitative detection of L. monocytogenes from stainless steel, plastic (polystyrene), and ceramic environmental surface samples. The NEMIS method is the first chemiluminescence detection system based on a novel, patented, dioxetane compound.

Performance and usefulness of a novel automated immunoassay HISCL SARS-CoV-2 Antigen assay kit for the diagnosis of COVID-19

Here, we aimed to evaluate the clinical performance of a novel automated immunoassay HISCL SARS-CoV-2 Antigen assay kit designed to detect the nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This kit comprises automated chemiluminescence detection systems. Western blot analysis confirmed that anti-SARS-CoV antibodies detected SARS-CoV-2N proteins. The best cut-off index was determined, and clinical performance was tested using 115 nasopharyngeal swab samples obtained from 46 patients with coronavirus disease 2019 (COVID-19) and 69 individuals who tested negative for COVID-19 through reverse transcription quantitative polymerase chain reaction (RT-qPCR). The HISCL Antigen assay kit showed a sensitivity of 95.4% and 16.6% in samples with copy numbers > 100 and < 99, respectively. The kit did not cross-react with human coronaviruses causing seasonal common cold and influenza, and none of the 69 individuals without COVID-19 were diagnosed with positive results. Importantly, 81.8% of the samples with low virus load (< 50 copy numbers) were diagnosed as negative. Thus, using HISCL antigen assay kits may reduce overdiagnosis compared with RT-qPCR tests. The rapid and high-throughput HISCL SARS-CoV-2 Antigen assay kit developed here proved suitable for screening infectious COVID-19 and may help control the pandemic.

Modified FIA-CL system for the on-line analysis of Pb(II) in aqueous solution, following treatment with chemically modified tomato peel as a biosorbent

Low waste generation represents a comprehensive orientation in analytical chemistry. It also forms a goal of flow injection analysis (FIA). The current research aims at modifying the injection part of the lucigenin-H2O2-OH- Pb(II) chemiluminescence detection system with flow injection analysis (FIA-CL) for an online Pb(II) analysis. The modified system was employed to determine the Pb(II)concentration. This was followed by treatment with crude tomato peels as an absorbent as tomato peels were treated with NaOH, carbonized tomato peels with HCl, and carbonized tomato peels with H2SO4. Under optimum experimental conditions, a calibration graph, represented by peak height (mV), was constructed based on plotting the chemiluminescence (CL) intensity, against (μg.ml−1) Pb(II) concentration, 10–90 μg.ml−1 range, 0.9913 correlation coefficient. Langmuir and Freundlich, used as isotherm models to verify the equilibrium results. The adsorption of Pb(II) on crude tomato peels and treated tomato peel was followed by the Langmuir model due to the high correlation coefficient (R2).

A Comparison of Commercially Available Screen-Printed Electrodes for Electrogenerated Chemiluminescence Applications.

We examined a series of commercially available screen-printed electrodes (SPEs) for their suitability for electrochemical and electrogenerated chemiluminescence (ECL) detection systems. Using cyclic voltammetry with both a homogeneous solution-based and a heterogeneous bead-based ECL assay format, the most intense ECL signals were observed from unmodified carbon-based SPEs. Three commercially available varieties were tested, with Zensor outperforming DropSens and Kanichi in terms of sensitivity. The incorporation of nanomaterials in the electrode did not significantly enhance the ECL intensity under the conditions used in this evaluation (such as gold nanoparticles 19%, carbon nanotubes 45%, carbon nanofibers 21%, graphene 48%, and ordered mesoporous carbon 21% compared to the ECL intensity of unmodified Zensor carbon electrode). Platinum and gold SPEs exhibited poor relative ECL intensities (16% and 10%) when compared to carbonaceous materials, due to their high rates of surface oxide formation and inefficient oxidation of tri-n-propylamine (TPrA). However, the ECL signal at platinum electrodes can be increased ∼3-fold with the addition of a surfactant, which enhanced TPrA oxidation due to increasing the hydrophobicity of the electrode surface. Our results also demonstrate that each SPE should only be used once, as we observed a significant change in ECL intensity over repeated CV scans and SPEs cannot be mechanically polished to refresh the electrode surface.

Fiber bundle-based chemiluminescence array detection.

Chemiluminescence (CL) is a dominant technology in clinical diagnosis. In order to meet the increasing demand for the sensitive and simultaneous detection of chemiluminescence from multiple samples, the development of multiplex analysis on a single chip is highly desired. However, most chemiluminescence detection systems for multiple samples are still simple lens-based optical imaging systems, and a compromise must always be made between a large aperture (required by the weak chemiluminescence) and a large field of view (required by the size of the sample array). In this paper, we report a fiber bundle-based chemiluminescence detection system for the simultaneous and efficient detection of multiple chemiluminescent samples. In this system, one side of the fiber bundle is directly coupled to the optically active surface of a charge-coupled device (CCD), while the other end is divided into many sub-bundles that are aligned above the samples in a chemiluminescence array to collect their chemiluminescence. Taking advantage of the large numerical aperture and high transmittance of optical fibers, this system shows about a 50 times increase in chemiluminescence collection efficiency over the lens-based imaging system. Moreover, it shows no vignetting effect that is inevitable in a lens-based imaging system with a large field of view. This work provides a promising method for multiple sample chemiluminescence detection, and should find application in bioassays.

Thyroid Hormone Reference Interval- Evidence from Alappuzha District, Kerala State, India

Introduction: Thyroid diseases are one of the most common endocrine disorders not only in India, but worldwide. Most commonly done biochemical tests to diagnose thyroid disorders are Thyrotropin (TSH), thyroid hormones {free thyroxine (FT4) and free triiodothyronine (FT3)} in serum. The Reference Interval (RI) is influenced by a variety of factors like diet, genetics, iodine nutritional status and thyroid autoimmunity. Hence, the reference values of thyroid function tests commonly used in the clinical laboratories are derived from data from the western population and may not be applicable for Indian population. Aim: To establish RI for thyroid hormones in the coastal area of Alappuzha District in Kerala. Materials and Methods: This community-based study included 228 adults in the age group 18-80 years. TSH, FT3, FT4, Thyroperoxidase antibody (TPOAb) and anti- thyroglobulin antibodies (TgAb) were analysed on an automated immunoassay system Access 2 Beckman Coulter using a direct chemiluminescence detection system. RIs were calculated according to International Federation of Clinical Chemistry (IFCC) recommendation using IBM SPSS version 20.0 for windows. Results: RIs for serum TSH, FT4 and FT3 were calculated as 0.11-6.39 mIU/L, 0.58-4.66 ng/dL and 0.72-4.66 pg/mL. No significant age and gender difference in the RIs are noted. Conclusion: In this study, RI established in the local reference population found to be different from those reported by previous studies conducted in other geographical areas.

Performance verification of a new domestic chemiluminescence detection system.

BackgroundProcalcitonin (PCT) is an acute phase response protein, which can be used as an indicator for early diagnosis of infection. At present, the main detection methods for PCT are electrochemiluminescence and enzyme-linked immunofluorescence. We aimed to explore the accuracy of PCT determination in a domestic chemiluminescence detection system and its correlation with other systems.MethodsClinical specimens were collected, and the precision, linearity, biological reference interval, contamination rate, Clinical reportable scope, and methodological comparison of the determination of PCT in a Chinese chemiluminescence detection system were evaluated and preliminarily verified by referring to Clinical and Laboratory Standards Institute (CLSI) documents or industry standards.ResultsThe results of precision verification showed that the coefficient of variation (CV) values of the variation coefficient of precision in the samples of low and high values were 2.07% and 0.83% respectively, while the CV values of the total variation coefficient of precision were 3.05% and 1.81% respectively; these findings all met the experimental requirements. The results of linear verification test showed that the linear range was 0.006–96.96 ng/mL, and the linear relationship was well within the detection range (R2 =0.9891). The biological reference interval and the carrying contamination rate were also verified. The clinical reportable range was 0.02–369.585 ng/mL. The results showed that the correlation coefficient between the Mindray CL900I and the Roche E602 was 0.9986, and that between the Mindray CL900I and the Snibe 2000 was 0.983. Meanwhile, when the PCT was higher than 0.1 ng/mL, the correlation coefficient was 100%.ConclusionsThe domestic chemiluminescence detection system has a good performance in the determination of calcitonin, as indicated by the measures of precision, linearity, biological reference interval, carrying contamination rate, and Clinical reportable scope, and can thus be used for clinical specimen detection. The results of methodological comparison showed that the correlation coefficient between the Mindray CL900I and Roche E602 was 0.9986, while the correlation coefficient between the Mindray CL900I and the Snibe 2000 was 0.983. The test results were consistent with the experimental requirements.

A review of recent developments based on chemiluminescence detection systems for pesticides analysis.

Chemiluminescence is one of the most coveted methods for sensitive determination of pesticides in food and environmental samples. To date, many methods have been developed for qualitative and quantitative analysis of pesticides, ranging from traditional to advanced methods. This study outlines the progress in the conventional and advanced analytical methods, coupled to a chemiluminescence detection system, that are employed for the determination of pesticides in food and environmental samples. Different analytical methods including chromatographic methods, flow-based systems, and paper-based systems are reviewed in this paper. As well, new advances in the application of nanomaterials, aptamer, and molecularly imprinted polymers are highlighted. We also address the challenges and difficulties associated with these methods. Finally, we highlight the future direction in this active field of research.

Effect of temperature maintenance by forced-air warming blankets of different temperatures on changes in inflammatory factors in children undergoing congenital hip dislocation surgery.

BackgroundHypothermia is associated with many adverse clinical outcomes in pediatric patients, and thus, it is important to find an effective and safe method for preventing peri-operative hypothermia and its associated adverse outcomes in pediatric patients. This study aimed to investigate the effect of forced-air warming blankets with different temperatures on changes in the transforming growth factor-β (TGF-β), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-10 levels in children undergoing surgical treatment for developmental displacement of the hip (DDH).MethodsThe study included 123 children undergoing surgery for DDH under general anesthesia. The patients were randomly assigned to three groups, using a random number table: the 32, 38, and 43°C groups according to the temperature setting of the forced-air warming blankets. For each patient, body temperature was recorded immediately after anesthesia induction and intubation (T0), at initial incision (T1), at 1 h after incision (T2), at 2 h after incision (T3), at the end of surgery (T4), immediately upon return to the ward after surgery (T5), and then at 12 h (T6), 24 h (T7), 36 h (T8), and 48 h (T9) after the surgery. The serum levels of TGF-β, TNF-α, IL-1β, and IL-10 were measured at T0 and T4 for all groups.ResultsThe number of patients with fever in the 38°C group was significantly less than those in the 32 and 43°C groups (χ2 = 6.630, P = 0.036). At T0, the body temperatures in the 38 and 43°C groups were significantly higher than that in the 32°C group (F = 17.992, P < 0.001). At T2, the body temperature was significantly higher in the 43°C group than those in the 32 and 38°C groups (F = 12.776, P < 0.001). Moreover, at T4, the serum levels of TGF-β (F = 3286.548, P < 0.001) and IL-10 (F = 4628.983, P < 0.001) were significantly increased in the 38°C group, and the serum levels of TNF-α (F = 911.415, P < 0.001) and IL-1β (F = 322.191, P < 0.001) were significantly decreased in the 38°C group, compared with the levels in the 32 and 43°C groups.ConclusionForce-air warming blankets set at 38°C maintained stable body temperature with less adverse outcome and effectively inhibited the inflammatory response in pediatric patients undergoing surgery for DDH.Clinical trial registrationChiCTR1800014820; http://www.chictr.org.cn/showproj.aspx?proj=25240.

Paper-based chemiluminescence and colorimetric detection of cytochrome c by cobalt hydroxide decorated mesoporous carbon

The detection and measurement of Cytochrome C (Cyt c) has a large impact on the early detection of various types of cancers. So there is a need for developing simple and rapid methods that can be offset by advances in the use of test strips. In this work, a chemiluminescence (CL) and colorimetric aptasensor based method for highly sensitive detection of Cyt c in solution and on paper is introduced. We found that new nano-based material composed of β-Co(OH)2 nanoplates anchored on ordered mesoporous carbon (CMK) could be a sufficient catalyzer in chemiluminescence and colorimetric systems. In the presence of Cyt c, its specific aptamers would bind to Cyt c and β-Co(OH)2 CMk can become free thus enhancing the intensity. While in the absence of Cyt c, a weak CL signal was produced, because β-Co(OH)2 CMK will be surrounded by aptamers. The proposed aptasensor exhibited a wide dynamic range from 5.0 × 10−8–1.0 × 10−3 M (R2 = 0.99) with a detection limit of 1.0 × 10−9 M in colorimetric and 10 × 10−13–5.0 × 10−9 M (R2 = 0.99) and a detection limit of 2.0 × 10−14 M in chemiluminescence detection systems, which was applicable for the determination of Cyt c efficiently. Also, we tested this strategy on paper for both colorimetric and chemiluminescence detection that showed the convenient response according to the obtained results.

Development of &amp;lt;i&amp;gt;α&amp;lt;/i&amp;gt;-Amino Acid Detection with Peroxyoxalate Chemiluminescence by Using Water-Acetonitrile-Ethyl Acetate Mixed Solution

Peroxyoxalate chemiluminescence was, for the first time, examined by using ternary mixed solutions of water-hydrophilic/hydrophobic organic solvent. Eosin Y as a model fluorescence compound was dissolved with the ternary solutions of water (1.0 mM carbonate buffer, pH 9.0)-acetonitrile-ethyl acetate, water-rich of 15:3:2 volume ratio and organic solvent-rich of 3:8:4 volume ratio, to which bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide chemiluminescence reagent were added. The chemiluminescence observed with the ternary solutions, especially the organic solvent-rich solution, showed a larger signal than that observed with the water only solution or water-acetonitrile mixed solution. Chemiluminescence in the presence of twenty types of α-amino acid was similarly examined by using the ternary organic solvent-rich solution. The chemiluminescence of three α-amino acids with fluorescence properties was enhanced with the ternary solution. The data reported here may contribute to development of a new, sensitive peroxyoxalate chemiluminescence detection system.

Modified VG-CL Detection System for Baseline Assessment of Dimethylsulphide and Dimethylsulphoniopropionate in Tropical Atlantic Seawater

Several studies have been carried out to measure the concentrations of dimethylsulphide (DMS) and dimethylsulphoniopropionate (DMSP) in coastal and open marine ecosystems. The present study attempted the fabrication of a cost-effective, highly sensitive and portable detection system based on vapour generation and chemiluminescence for a pilot assessment and determination of DMS and DMSP concentrations in tropical Atlantic seawater samples. The Sultan Beach and Badagry parts of the Atlantic Ocean were chosen as designated locations for this study. Vapour generation chemiluminescence (VG-CL) detection system is a device that can measure the concentration (nM) of DMS and DMSP by allowing DMS vapour which in turn reacts with ozone to produce chemiluminescence which can be detected by a photomultiplier (PMT). The mean concentrations of DMS and DMSP in the surface seawater at the sampling location were 5.80±0.71 to 19.40±0.57 nM and 11.00±0.42 to 34.70±1.13 nM, respectively. The average minimum and maximum concentrations of DMS and DMSP across the location were between 0 and 40.91 nM, respectively. This study serves as a baseline measurement of DMS concentrations in the tropical Atlantic Ocean (Lagos).

Flow microdialysis sampling-chemiluminescent detection coupled with molecular docking for the investigation of binding behavior between salbutamol and DNA

The investigation of the binding behavior between drug and DNA provides basic information for understanding pharmacological and toxicologic mechanisms of many drugs. Herein, a facile chemiluminescent (CL) method for investigating the binding behavior between salbutamol and calf thymus DNA (ct-DNA) was established by utilizing flow microdialysis sampling technique. In a reaction equilibrium solution of salbutamol and ct-DNA, free salbutamol was extracted by a microdialysis probe, and then injected into a flow-injection CL detection system to quantitate its concentration. The binding constants of salbutamol acquired by Klotz analysis and Scatchard analysis were 2.97 × 104 M−1and 2.99 × 104 M−1, respectively. Salbutamol showed one sort of binding site on ct-DNA. Meanwhile, the three-dimensional spatial structure of the binding mode was investigated by molecular docking. The results indicate that the binding mode of salbutamol to ct-DNA was groove binding. The hydrogen bonds were primary driving force for the direct recognition of salbutamol by ct-DNA. This proof-of-principle method paves a pathway to investigate the binding behavior between small-molecular drug and DNA, and provides a theoretical guidance for designing DNA-targeting drugs.

Field Assessment and determination of concentration levels of Dimethylsulphide in Tropical Seawater

Dimethylsulphide (DMS) is an important climatically reactive trace gas which is emitted from the seawater to the atmosphere. It undergoes various oxidative reactions to produce cloud condensation nuclei, which affect the earth radiation budget. DMS and its precursor dimethylsulphoniopropionate (DMSP) were measured using a modified vapour generation – chemiluminescence (VG-CL) detection system that was designed for this study. The chosen sampling locations used for the measurement were Nigeria Institute of oceanography and marine research (NIOMR) and ELEGUSHI. They are situated along the Gulf of Guinea. The modified VG-CL analyser was used for trace analysis of dimethylsulphide in the study area. The mean concentrations of DMS in the surface seawater at the two sampling locations ranged from 0 to 35.53±2.34 nM, 10.67±0.28 and 44.95±0.27 nM, respectively. The average minimum and maximum concentrations of DMS and DMSP across the two locations were between 0 and 44.95 nM, respectively. The concentrations of DMS and DMSP were compared across the sampling locations, and the observed pattern showed that DMS for ELEGUSHI has a higher concentration than NIOMR. The result further revealed that the concentration of the DMS is a function of the sea surface temperature (SST) of the aquatic ecosystem. The observed DMS concentration data of this study provides a baseline measurement for the tropical Atlantic Ocean (Lagos), thus a significant addition to the global DMS database.

Janus kinase 1/2 inhibition for the treatment of autoinflammation associated with heterozygous TNFAIP3 mutation

Janus kinase 1/2 inhibition for the treatment of autoinflammation associated with heterozygous TNFAIP3 mutation

A Chemiluminescent Method for the Detection of H₂O₂ and Glucose Based on Intrinsic Peroxidase-Like Activity of WS₂ Quantum Dots.

Currently, researchers are looking for nanomaterials with peroxidase-like activity to replace natural peroxidase enzymes. For this purpose, WS2 quantum dots (WS2 QDs) were synthesized via a solvothermal method, which improved the mimetic behavior. The resulting WS2 QDs with a size of 1–1.5 nm had a high fluorescence emission, dependent on the excitation wavelength. WS2 QDs with uniform morphology showed a high catalytic effect in destroying H2O2. The peroxidase-like activity of synthesized nanostructures was studied in H2O2 chemical and electrochemical reduction systems. The mimetic effect of WS2 QDs was also shown in an H2O2–rhodamine B (RB) chemiluminescence system. For this aim, a stopped-flow chemiluminescence (CL) detection system was applied. Also, in order to confirm the peroxidase-like effect of quantum dots, colorimetry and electrochemical techniques were used. In the enzymatic reaction of glucose, H2O2 is one of the products which can be determined. Under optimum conditions, H2O2 can be detected in the concentration range of 0–1000 nmol·L−1, with a detection limit of 2.4 nmol·L−1. Using this CL assay, a linear relationship was obtained between the intensity of the CL emission and glucose concentration in the range of 0.01–30 nmol·L−1, with a limit of detection (3S) of 4.2 nmol·L−1.

Surface molecular imprinting and powerfully enhanced chemiluminescence emission by Cu nanoclusters/MOF composite for detection of tramadol

Herein, a high performance chemiluminescence (CL) system is developed for the sensitive detection of tramadol. The CL reaction is based on the direct oxidation of rhodamine 6 G (R6 G) by potassium permanganate (KMnO4), producing an ultra-weak emission. It was found that copper nanoclusters encapsulated in copper-based two-dimensional metal-organic frameworks (CuNCs@CuMOF) create a tremendous enhancing effect on the observed emission. A probable mechanism was also suggested for CL emission based on the catalytic effects of nanomaterial and chemiluminescence resonance energy transfer (CRET) events. Besides, it was observed that tramadol caused a relatively selective increasing effect on the CL emission of R6 G-KMnO4-CuNCs@CuMOF system. In order to guarantee a selective response for tramadol, an extraction process using molecularly imprinted polymer modified Fe3O4@SiO2 nanoparticles (MIP-Fe3O4@SiO2 NPs) was applied before the CL analysis. The dispersed MIP-Fe3O4@SiO2 NPs showed high specificity for the extraction of tramadol from its samples. The combination between the high improved CL detection system and the efficient extraction process caused an ultrasensitive and selective determination method for tramadol. The best linear calibration graph was obtained in the concentration range of 0.0030–2.5 μM tramadol, with a detection limit (3Sb/m) of 0.80 nM. The illustrated CL method was tested for the quantification of tramadol in biological fluids, which led to the acceptable and reliable results.