Chemiluminescence Detection System Research Articles

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.

Point of care upconversion nanoparticles-based lateral flow assay quantifying myoglobin in clinical human blood samples

Reliable detection and quantification of myoglobin (Mb) in blood plasma is of significance for clinical diagnosis and management of acute myocardial infarction (AMI). Here, we describe a homemade platform combining efficient core-shell upconversion nanoparticles (UCNPs) and lateral flow assay (LFA) for ultrasensitive and specific fluorescence ratiometric evaluation of Mb in clinical blood samples. After a systematic optimization, this platform was able to reach a limit of detection as low as 0.21 ng/ml, a linear range of 0.5–400 ng/ml, a recovery rate of 90.6–110.5%, an inter-assay coefficient of variation (CV) of 3.0–6.2%, an intra-assay CV of 8.8–13.6%, and a detection time of 10 min. Furthermore, the acquired concentration results were unresponsive to the interference of high-bilirubin, high-lipids, and hemolysis, and a range of other biomarkers (CRP, PCT, and BSA), substantiating robust Mb-specific detection. Importantly, the platform showed a significant linear correlation (R2 = 0.9484) with clinically used Abbott Chemiluminescence detection system (CLDS) on evaluation of Mb concentration in 50 clinical human blood plasmas. The achievement of rapid, sensitive and reliable quantification of Mb in clinical plasma promises the prevalent use of the described platform for on-field diagnosis or rule-out of AMI in clinical practice.

Chemiluminescence detection with microfluidics for innovative in situ measurement of unbound cobalt ions in dynamic equilibrium with bound ions in binding study with polyethyleneimine and its functionalized nanoparticles

This work reports a novel method for in situ measurement of binding of cobalt ions to polyethyleneimine (PEI) and polyethyleneimine-functionalized poly (methyl methacrylate) nanoparticles (PEI-NPs) using simple microfluidics with a chemiluminescence detection system. The catalytic effect of free cobalt ion in solution on the luminol-hydrogen peroxide chemiluminescence was employed for the detection of unbound cobalt in dynamic equilibrium with cobalt bound to PEI or PEI-NPs. Many binding measurements lead to incorrect estimation of free metal ions due to insufficient separation of bound and free ions. The catalytic activity of only unbound cobalt ion on the luminol reaction was demonstrated by observing that PEI and PEI-NPs alone did not give chemiluminescence. Also, both Co-PEI and Co-PEI-NPs complexes gave no chemiluminescence when cobalt ion is fully bound with excess PEI or PEI-NPs. In addition diethylenetriamine (dien) as a model ligand to completely bind the cobalt ions was also employed as further confirmation. The chemiluminescence measurement employing microfluidics was then successfully applied for the measurement of binding cobalt ion to PEI and PEI-NPs. This in situ measurement of binding does not require filtration of the two species. As there is no perturbation of equilibrium, an accurate binding measurement can therefore be successfully performed. Experimental parameters, such as concentrations of polymers and cobalt ions, and equilibration time were investigated. Analysis of the experimental data employed the binding equation derived assuming independent and equivalent binding sites of the polymer for the metal ions. Also the binding constant of cobalt ions with PEI-NPs is first reported employing chemiluminescence detection. This work provides quantitative determination of the binding constant and total binding capacity of PEI and PEI-NPs with cobalt ions using chemiluminescence detection and microfluidics as an innovative in situ measurement of the unbound cobalt ions.

Effects of siRNA Targeting Interference of APE1 Gene on Proliferation and Apoptosis of Glioma Cells

This paper explored the application of RNA in cancer gene therapy. Second, the effect of the recombinant plasmid APE1 siRNA on the expression of APE1 protein was observed. In addition, the proliferation of cells in apoptosis and the radiosensitivity of human glioma U251 cells were also discussed. U251 cells were divided into control group, negative group and APE1siRNA group for culturing. There were two holes in each group, and independent experiments were repeated three times. The expression of APE1 protein in U251 cells was detected by Western blot experiments for siRNA transfection. The siRNA cells were transfected, while another group of FAM fluorescent labeled non-sense sequence siRNA was transfected to determine the transfection rate and extract the total protein of the cell. BCA protein assay kit was used for determining the concentration. Meanwhile, 50g sample and SDS-polypropylene diamine gel were prepared. Coomassie blue staining was used to observe the protein electrophoresis, after which the protein on the gel was transferred to the PVDF membrane and then developed in a chemiluminescent detection system with specific antibodies. The β -action test was used as an internal controller, while the optical density scanner was used to detect the gray value of the target strip. The relative expression of target protein was equal to the target band gray value or the same sample reference value of gray. MTT method was used to detect the cell growth curve experiments, while AO or EB method was used to detect the apoptosis rate of glioma cells. SPSS17.0 was used for statistical analysis. The results show that the APE1 siRNA expression plasmid was successfully introduced into human glioma cells by RNA interference, which can reduce the expression of APE1 in cells. It was confirmed that the reduction of APE1 protein could inhibit proliferation and promote the apoptosis of glioma cells. Third, APE1 targeting interference may be an effective gene therapy strategy for human glioma, which can provide an experimental basis for the clinical gene therapy of glioma.

Improved peroxidase mimetic activity of a mixture of WS2 nanosheets and silver nanoclusters for chemiluminescent quantification of H2O2 and glucose

It is reported that a mixture of WS2 nanosheets (WS2 NS) and silver nanoclusters (AgNCs) displays strongly enhanced peroxidase-mimicking activity. The catalytic effect of the mixture was studied by colorimetry, fluorometry, chemiluminescence (CL) and electrochemistry. The effect is interpreted in terms of a difference between the Fermi energy level of the two nanomaterials. This leads to the formation of charge separation regions which act as active sites for enzyme mimetic interaction with the substrates. The mixture of WS2 NS and AgNCs was exploited for the non-enzymatic determination of H2O2 and glucose. A stopped-flow method was applied as a sensitive CL detection system using the bicarbonate-H2O2 reaction. The mixture has a powerful peroxidase mimicking activity on the bicarbonate-H2O2 CL reaction, and this effect is much larger than that of any single constituent. In addition, the CL emission is improved several times by using the stopped-flow technique. Under optimum condition, H2O2 can be determined in the2.5-1500 nM concentration range. Moreover, glucose levels in human serum can be quantified via glucose oxidase based oxidation which leads to the generation of H2O2. Using this CL assay, a linear relationship was obtained between the intensity of the CL emission and glucose concentration in the range of 0.03-20μM, with a limit of detection (3S) of 13 nM. Graphical abstract An enhanced peroxidase-like catalytic activity for WS2 nanosheets (WS2 NS) was revealed in the presence of silver nanoclusters (AgNCs), and was exploited for the non-enzymatic determination of H2O2,and ofglucose (via glucose oxidase; GOx) using a stopped-flow CL method.

Simplex optimization of the variables influencing the determination of pefloxacin by time-resolved chemiluminescence

A new chemiluminescence (CL) detection system combined with flow injection analysis (FIA) for the determination of Pefloxacin is proposed. The determination is based on an energy transfer from Pefloxacin to terbium (III). The metal ion enhances the weak CL signal produced by the KMnO4/H2SO3/Pefloxacin system. A modified simplex method was used to optimize chemical and instrumental variables. The influence of the interaction of the permanganate, Tb (III), sodium sulphite and sulphuric acid concentrations, flow rate and injected sample volume was thoroughly investigated by using a modified simplex optimization procedure. The results revealed a strong direct relationship between flow rate and CL intensity throughout the studied range that was confirmed by a gamma test. The response factor for the CL emission intensity was used to assess performance in order to identify the optimum conditions for maximization of the response. Under such conditions, the CL response was proportional to the Pefloxacin concentration over a wide range. The detection limit as calculated according to Clayton's criterion 13.7μgL−1. The analyte was successfully determined in milk samples with an average recovery of 100.6±9.8%.

Quantitative Analysis of Reactive Oxygen Species Photogenerated on Metal Oxide Nanoparticles and Their Bacteria Toxicity: The Role of Superoxide Radicals.

Ecotoxicity of engineered nanoparticles (NPs) has become the focus of considerable attention because of their wide applications. Reactive oxygen species (ROS) play important roles in the toxicity mechanisms of engineered metal oxide NPs. This work aimed to understand quantitatively the contribution of photogenerated ROS on metal oxide NPs to their toxicity. The dynamic generation of O2•-, •OH, and H2O2 in aqueous suspensions of photoilluminated metal oxide nano- and bulk particles (TiO2, ZnO, V2O5, CeO2, Fe2O3, and Al2O3) was measured by a continuous-flow chemiluminescence (CFCL) detection system. Superoxides were generated on all six nanoparticles as well as bulk TiO2 and ZnO, with nano TiO2 producing the highest concentration (180 nM). Hydroxyl radicals were detected on both nano- and bulk TiO2 and ZnO, whereas H2O2 was detected only on TiO2 and ZnO nanoparticles. The generation of ROS can in general be interpreted by the electronic structures and surface defects of the NPs and the ROS redox potentials. Furthermore, acute toxicity of the six metal oxide particles to a luminescent bacterium, P. phosphoreum 502 was assessed after photoillumination. The toxicity effect was attributed to the long-lived O2•- radicals on the nanoparticlce, and its potency follows the order of TiO2 > ZnO > V2O5 > Fe2O3 > CeO2 > Al2O3, which is the same as the order of the O2•- concentration measured by CFCL. Our work revealed quantitatively the important role superoxide radicals play in the toxicity of various metal oxide nanoparticles after photoillumination.

Helicobacter pylori modulates cisplatin sensitivity in gastric cancer by down-regulating miR-141 expression.

In Figure 4B in the above article, the figures for KEAP-1 expression was matched with wrong pictures. This error does not affect the results in the paper or the interpretation of the data. The corrected panel appears below. We apologize for any confusion this error may have caused. In Material and Methods/Western blotting section, STAT4 should be replaced by KEAP-1. Western blotting (corrected) Total proteins were prepared from both cells, quantities using a protein assay (BCA method, Thermo, USA). The KEAP-1 protein was analyzed by Western blot analysis using KEAP-1 Rabbit Monoclonal Antibody, and GAPDH was used as an internal control. Proteins were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) transferred to polyvinylidene fluoride (PVDF) membrane, blocked in 5% dry milk at room temperature for 1 hour and immunostained with antibodies at 4°C overnight using anti-KEAP-1 (1:1000, CST, USA) and anti-GAPDH (1:5000, sigma, USA). All results were visualized through a chemiluminescent detection system (Pierce ECL Substrate Western blot detection system, Thermo, Pittsburgh, PA) and then exposed in Molecular Imager ChemiDoc XRS System (Bio-Rad, Hercules, CA). The authors would like to apologize for any confusion or inconvenience caused by this error.

Pollutant Formation during the Occurrence of Flame Instabilities under Very-Lean Combustion Conditions in a Liquid-Fuel Burner

Recent advances in gas turbine combustor design are aimed at achieving low exhaust emissions, hence modern aircraft jet engines are designed with lean-burn combustion systems. In the present work, we report an experimental study on lean combustion in a liquid fuel burner, operated under a non-premixed (single point injection) regime that mimics the combustion in a modern aircraft engine. The flame behavior was investigated in proximity of the blow-out limit by an intensified high rate Charge-Coupled Device (CCD) camera equipped with different optical filters to selectively record single species chemiluminescence emissions (e.g., OH*, CH*). Analogous filters were also used in combination with photomultiplier (PMT) tubes. Furthermore this work investigates well-mixed lean low NOx combustion where mixing is good and generation of solid carbon particulate emissions should be very low. An analysis of pollutants such as fine particles and gaseous emissions was also performed. Particle number concentrations and size distributions were measured at the exhaust of the combustion chamber by two different particle size measuring instruments: a scanning mobility particle sizer (SMPS) and an Electrical Low Pressure Impactor (ELPI). NOx concentration measurements were performed by using a cross-flow modulation chemiluminescence detection system; CO concentration emissions were acquired with a Cross-flow modulation Non-dispersive infrared (NDIR) absorption method. All the measurements were completed by diagnostics of the fundamental combustor parameters. The results herein presented show that at very-lean conditions the emissions of both particulate matter and CO was found to increase most likely due to the occurrence of flame instabilities while the NOx were observed to reduce.

Repeatability of a terminal restriction fragment telomere length assay on red drum fin tissue

Telomere length measurements are becoming increasingly popular in biology as a non-lethal tool for estimating organisms’ biological conditions. One particularly appealing application of telomere length measurements for conservation biologists is genetic age estimation. Most age estimation methods require animals to be sacrificed followed by the dissection and sectioning of calcified structures. Because telomeres degrade over time, telomere lengths may provide non-lethal and minimally invasive tool for estimating age. Furthermore, telomere length may also be useful for predicting longevity and fitness. Traditionally, telomere lengths have been measured using terminal restriction fragment (TRF) methodology; however, there is no one standard laboratory procedure to estimate the size of these fragments, and few studies supply repeatability data for the respective methods. While TRF telomere length assays are applicable to all organisms with known telomere repeat motif sequences, inconsistencies in TRF methodology include template DNA treatment, restriction enzymes used, gel electrophoresis methods, and probe/detection methods. Here we present a study documenting repeatability data for a specific laboratory procedure for estimating telomere length using two common restriction enzymes, denaturing pulsed field gel electrophoresis, and a chemiluminescent detection system for three replicates of 16 individual red drum collected in South Carolina. The data were analyzed following traditional methods using an average across the entire TRF distribution, which represents all TRF lengths found in the sample; and following non-traditional methods, where only a subsample of the TRF distributions are analyzed. Our results demonstrate a strong correlation among average TRF lengths between replicates while analyzing the entire TRF distribution; however, our results show a decreasing trend of consistency between replicates as smaller portions of the TRF distribution were analyzed. These results suggest our method provides a repeatable estimate of average TRF length in a sample, and we urge that caution should be exercised when subsampling TRF distributions for telomere length analysis. Repeatability data not only validate the assay producing the data, but also may allow researchers to develop standard optimal criteria to balance cost and extent of their study design.

Ultra-sensitive HPLC-photochemical reaction-luminol chemiluminescence method for the measurement of secondary amines after nitrosation

A novel method for the determination of secondary amines at the nanomolar level was developed. The method is based on the nitrosation reaction of secondary amines, with the generated N-nitrosamines being measured using an HPLC separation, photochemical reaction, and chemiluminescence detection system. The efficient nitrosation of secondary amines was performed using sodium nitrite (200 mM) and acetic acid (0.8 M) at 80 °C over 60 min. Although compounds bearing OH and SH functional groups also underwent the nitrosation reaction, the sensitivity of these compounds was 1000 times lower than that of the secondary amines. Our method was applied to the determination of low molecular weight secondary amines, including dimethylamine, morpholine, pyrrolidine, diethylamine, and piperidine, giving method detection limits of 0.7 nM, 0.2 nM, 0.4 nM, 0.7 nM, and 1.5 nM, respectively. The calibration curves were linear in the range of 5–100 nM. We then applied this method for the detection and quantification of these secondary amines in samples of tap water, river water, treated wastewater, and sea water. Dimethylamine was detected at concentrations up to 15.4 nM, <0.7 nM, and 48.5 nM in tap water, river water, and treated wastewater samples, respectively, with recoveries ranging from 94 to 103%. Other amines were also detected at nanomolar levels. These results indicate that our proposed method can be applied to the analysis of secondary amines in various environmental water samples. To the best of our knowledge, the proposed method is one of the most sensitive and selective methods for the determination of secondary amines without pre-concentration steps.

The performance of [-2]proPSA and prostate health index tumor markers in prostate cancer diagnosis

Abstract Background: Prostate-specific antigen (PSA) is an established tumor marker for the diagnosis of patients with prostate cancer. The aim of the study was to evaluate the performance of [-2]proenzyme PSA ([-2]proPSA) and prostate health index (PHI) tumor markers in the differential diagnosis between benign prostatic diseases and prostate cancer. Methods: Total PSA (tPSA), free PSA (fPSA) and [-2]proPSA were measured using antibody-based sandwich enzyme-linked immunosorbent assay with a chemiluminescent detection system in 110 patients, with a tPSA of 1.6–8.0 µg/L. The PHI and %[-2]proPSA were calculated from the PSA values mentioned above. The results were compared with histopathological examination results following a transrectal ultrasound-guided biopsy of the prostate. Results: For the prediction of a malignant histopathological result, the specificity at the 90% sensitivity level was 24.3% for [-2]proPSA, 32.4% for %[-2]proPSA, 28.4% for PHI, 18.9% for tPSA and 28.4% for the free-to-total PSA ratio. The area under the curve for [-2]proPSA, %[-2]proPSA, PHI, tPSA and the free-to-total PSA ratio was 0.663, 0.749, 0.742, 0.616 and 0.625, respectively. Conclusions: Our study found a moderate improvement over tPSA and %fPSA in detecting prostate cancer using the [-2]proPSA assay in patients with a tPSA range of 1.6–8.0 µg/L.

Genetic diagnosis of familial hypercholesterolaemia using a rapid biochip array assay for 40 common LDLR, APOB and PCSK9 mutations

Background and aimsFamilial hypercholesterolaemia (FH) leads to a lifelong increase in plasma LDL levels with subsequent increase in premature vascular disease. Early diagnosis and treatment is the key to effective management of this condition. This research aims to produce a simple and cost effective genetic test which could identify the majority (71%) of mutations causing FH in the UK and Ireland. MethodsThe Randox Biochip Array Technology was used to detect 40 point mutations in LDLR, APOB and PCSK9 genes, over two 5 × 5 arrays. This technology uses multiplex allele specific PCR and biochip array hybridisation, followed by a chemiluminescence detection system and software for automated mutation calling. ResultsThe FH biochip array assay was validated in the Belfast Genetics Laboratory using 199 cascade screening samples previously sequenced for known FH causing family mutations, the overall sensitivity was 98%. The assay was then used for routine testing of 663 patients with possible FH, from clinics across the UK and Ireland. A total of 49 (7.4%) mutation positive individuals were identified, however, for the clinics in England the detection rate was 12.9%. Further analysis of 120 biochip negative patients, using DNA sequencing, did not identify any false negatives. ConclusionsThe FH biochip array provides a rapid and reliable genetic test for the majority of FH causing point mutations in the UK and Ireland. A total of 32 samples can be run in 3 h. This allows clinics to evaluate additional patients for a possible diagnosis of FH such as patients with high LDL, patients with early onset coronary disease, and patients with relatives known to have FH.

A label-free strategy for measuring the affinity between monoclonal antibody and hapten using microdialysis sampling combined with chemiluminescent detection

It is of great importance to measure antibody affinity in the course of screening monoclonal antibody (McAb) for immunotherapy, immunoassay and immunological purification. Herein, by using terbutaline mouse McAb as a model, a novel label-free strategy based on on-line microdialysis (MD) sampling combined with flow injection chemiluminescent detection was designed for measuring antibody affinity to hapten in a homogeneous system. After this McAb incubated with its hapten, the unbound hapten was sampled on-line by the MD probe and injected into the chemiluminescent detection system for quantification. The obtained concentrations of the unbound hapten were treated with Scatchard analysis and Klotz analysis to calculate the affinity constant. The MD probe showed a recovery of 26.2% for terbutaline under the chosen conditions. The affinity constants obtained using Scatchard analysis and Klotz analysis were 4.9×106M−1 and 4.9×106M−1, respectively, showing negligible difference. The obtained affinity constants indicated that the investigated McAb was an antibody with medium affinity. The designed strategy provided a simple, rapid and low-cost approach for direct measurement of antibody affinity. Furthermore, it avoided the decrease of affinity, which was encountered frequently in the conventional approaches based on probe labeling of McAb and protein conjugation of hapten.

Determination of reactive oxygen generated from natural medicines and their antibacterial activity

Extracts of 16 natural medicine powders (Galla chinensis, Malloti cortex, Cassiae semen, Sophorae radix, Myricae cortex, Crataegi fructus, Gambir, Mume fructus, Geranii herba, Phellodendri cortex, Coptidis rhizoma, Swertiae herba, and Cinnamomi cortex) were assayed for reactive oxygen concentrations using the peroxyoxalate chemiluminescent detection system. High luminescence intensity was observed in Galla chinensis, Geranii herba, Malloti cortex, Myricae cortex, and Cinnamomi cortex. Additional experiments identified the reactive oxygen species as hydrogen peroxide.Galla chinensis generated 2.4×10−4mol/L hydrogen peroxide from a 1mg/mL solution. In bacterial growth tests, Galla chinensis extract had antibacterial activity against Escherichia coli, Staphylococcus aureus, Bacteroides thetaiotaomicron, Campylobacter sputorum biovar sputorum, Streptococcus salivarius thermophilus, Lactobacillus casei, and Bifidobacterium longum infantis. This antibacterial activity was decreased by the addition of catalase. It revealed that hydrogen peroxide which Galla chinensis produced participated in antibacterial activity.

Cholesterol-mediated Degradation of 7-Dehydrocholesterol Reductase Switches the Balance from Cholesterol to Vitamin D Synthesis

Cholesterol is detrimental to human health in excess but is also essential for normal embryogenesis. Hence, enzymes involved in its synthesis possess many layers of regulation to achieve balanced cholesterol levels. 7-Dehydrocholesterol reductase (DHCR7) is the terminal enzyme of cholesterol synthesis in the Kandutsch-Russell pathway, converting 7-dehydrocholesterol (7DHC) to cholesterol. In the absence of functional DHCR7, accumulation of 7DHC and a lack of cholesterol production leads to the devastating developmental disorder, Smith-Lemli-Opitz syndrome. This study identifies that statin treatment can ameliorate the low DHCR7 expression seen with common Smith-Lemli-Opitz syndrome mutations. Furthermore, we show that wild-type DHCR7 is also relatively labile. In an example of end-product inhibition, cholesterol accelerates the proteasomal degradation of DHCR7, resulting in decreased protein levels and activity. The loss of enzymatic activity results in the accumulation of the substrate 7DHC, which leads to an increased production of vitamin D. Thus, these findings highlight DHCR7 as an important regulatory switch between cholesterol and vitamin D synthesis.

A miniaturized chemiluminescence detection system for a microfluidic paper-based analytical device and its application to the determination of chromium(iii)

A miniaturized detection system for chemiluminescence that is generated on a microfluidic paper-based analytical device (μPAD) was developed using optical fibers and was applied to the determination of Cr(iii).

Considering the chemical energy requirements of the tri-n-propylamine co-reactant pathways for the judicious design of new electrogenerated chemiluminescence detection systems.

The introduction of a 'co-reactant' was a critical step in the evolution of electrogenerated chemiluminescence (ECL) from a laboratory curiosity to a widely utilised detection system. In conjunction with a suitable electrochemiluminophore, the co-reactant enables generation of both the oxidised and reduced precursors to the emitting species at a single electrode potential, under the aqueous conditions required for most analytical applications. The most commonly used co-reactant is tri-n-propylamine (TPrA), which was developed for the classic tris(2,2'-bipyridine)ruthenium(II) ECL reagent. New electrochemiluminophores such as cyclometalated iridium(III) complexes are also evaluated with this co-reactant. However, attaining the excited states in these systems can require much greater energy than that of tris(2,2'-bipyridine)ruthenium(II), which has implications for the co-reactant reaction pathways. In this tutorial review, we describe a simple graphical approach to characterise the energetically feasible ECL pathways with TPrA, as a useful tool for the development of new ECL detection systems.

Development of a Chemiluminescence Detecting System Based on FPGA

In order to detect weak chemiluminescence signal rapidly and high accurately, a chemiluminescence detection system is designed based on the core chip FPGA. The system uses a static injection mechanism as chemiluminescence reaction conduit. High-performance photodiode converts chemiluminescence signals into electrical signals replacing the traditional photomultiplier tube. It can meet the test requirements while reducing the cost of the detection system. The signal processing and storage system FPGA-based consists of A/D converter module, serial communication module, the keyboard scan control modules and memory modules. Nitrite ions in water samples are detected and the results show that in a certain concentration range the calibration curve of NO2-concentration and luminescence intensity is linear, the linear regression equation is Y = 0.4148X + 2.6508, and the correlation coefficient is R2= 0.9832. The relative standard deviation values are 2.7%(n=11).

A novel glucose sensor based on immobilization of glucose oxidase on the chitosan-coated Fe3O4 nanoparticles and the luminol–H2O2–gold nanoparticle chemiluminescence detection system

A novel and efficient glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated H2O2 was constructed by the effective immobilization of glucose oxidase (GOX) on the Fe3O4–chitosan (Fe3O4–CS) nanoparticles support. The covalent immobilization of enzyme was performed using glutheraldehyde (GA) as a cross-linking agent. (H2O2 was constructed by one covalent immobilization of glucose oxidase in glutaraldehyde-functionalized glass cell). In addition to catalyzes the luminol CL reaction, gold NPs offer excellent catalytic activity toward hydrogen peroxide generation as a result of enzymatic reaction between glucose oxidase and glucose. Based on response surface methodology (RSM), the optimal immobilization conditions for glucose oxidase were obtained as: enzyme to support ratio, 0.7; Immobilization pH, 6; cross-linking time, 75min; and glutaraldehyde (GA) concentration, 0.2%. The characterization of Fe3O4, Fe3O4–chitosan and Au nanoparticles was analyzed by XRD, FT-IR and SEM. The linear range of this novel method is 1×10−4 to 8.5×10−7molL−1 (R2=0.9956). The detection limit is 4.3×10−7molL−1. The relative standard deviation (RSD) <3.1% was obtained.