Chemiluminescence Assay for Uric Acid in Human Serum and Urine Using Flow-injection with Immobilized Reagents Technology

Analytical and Bioanalytical Chemistry. Jan, 2002  |  Pubmed ID: 11936107

A novel chemiluminescence (CL) flow sensor for the determination of uric acid in human urine and serum has been developed by using controlled-reagent-release technology. The reagents involved in the chemiluminescence (CL) reaction, luminol and periodate, are immobilized on anion-exchange resin packed in a column. After injection of water, chemiluminescence generated by released luminol and periodate in alkaline media is inhibited in presence of uric acid. By measuring the decreased chemiluminescence (CL) intensity the uric acid is sensed. The decreased response is linear in the 5.0-500.0 ng mL(-1) range, with a detection limit of 1.8 ng mL(-1). The flow sensor showed remarkable operational stability and could be easily reused for over 80 h with sampling frequency of 100 h(-1). The proposed sensor was applied to the determination of uric acid in human urine and serum, and monitoring metabolic uric acid in human urine with RSD less than 3.0%.

Determination of Picomole Amounts of Thiamine Through Flow-injection Analysis Based on the Suppression of Luminol-KIO(4) Chemiluminescence System

Journal of Pharmaceutical and Biomedical Analysis. May, 2002  |  Pubmed ID: 12008148

A continuous flow sensor for the determination of thiamine was constructed by using controlled-reagent-release technology in a FIA-CL system. The analytical reagents, luminol and KIO(4), were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and KIO(4), which were eluted from the column through H(2)O injection, was decreased in the presence of thiamine. The decreased CL intensity was linear with thiamine concentration in the range 3.3 pmol ml(-1)-6.7 nmol ml(-1); and the limit of detection was 1.0 pmol ml(-1) (3.). The whole process, including sampling and washing, could be completed in 0.5 min with a relative standard deviation of less than 3.0%. The flow sensor showed remarkable stability and could be easily reused over 80 h. The sensor proposed was tested in determination of thiamine in pharmaceutical preparation and human urine samples.

A New Green Analytical Procedure for Monitoring Sub-nanogram Amounts of Chlorpyrifos on Fruits Using Flow Injection Chemiluminescence with Immobilized Reagents

Journal of Agricultural and Food Chemistry. Jul, 2002  |  Pubmed ID: 12137462

A novel green method using flow injection chemiluminescence with controlled-reagent-release technology has been investigated for the rapid and sensitive monitoring of sub-nanogram amounts of chlorpyrifos. The analytical reagents involved in chemiluminescence (CL) reaction, luminol and periodate, were both immobilized on an anion-exchange column. The CL signals produced by the reaction between luminol and periodate, which were eluted from the column through water injection, were decreased in the presence of chlorpyrifos. The decrease of CL intensity was linear over the logarithm of concentration of chlorpyrifos ranging from 0.48 to 484.0 ng x mL(-1) (r(2) = 0.9969), and the limit of detection was 0.18 ng x mL(-1) (3sigma). At a flow rate of 2.0 mL x min(-1), the determination of chlorpyrifos, including sampling and washing, could be performed in 0.5 min with a relative standard deviation of less than <3.0%. The proposed method was applied successfully in an assay of remnant chlorpyrifos on fruits such as orange and shaddock with the recovery of 94.4-107.4%. The change of the concentration of chlorpyrifos in a water sample was also investigated, and the variation rate was 99.96% during 35 h in the open air.

Sensitive Determination of Sub-nanogram Amounts of Rutin by Its Inhibition on Chemiluminescence with Immobilized Reagents

Talanta. Apr, 2002  |  Pubmed ID: 18968605

An interesting inhibitory effect of rutin on the chemiluminescence (CL) reaction between luminol and periodate was reported, and this effect was used for the determination of rutin in medicine and human urine. The CL reagents, luminol and periodate, were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and periodate, which were eluted from the column through water injection, was decreased in the presence of rutin. Rutin was sensed by measuring the decrement of CL intensity, and which was observed to be linear over the logarithm of 0.1-30 ngml(-1) rutin concentration range, and the limit of detection was 0.03 ngml(-1) (3sigma). At a flow rate of 2.0 mlmin(-1), both sampling and washing could be performed in 0.5 min with a relative standard deviation of less than 3.0%. The method proposed offered reagent-less procedures and remarkable stability in the determination of rutin, and could be easily reused over 80 h. The method proposed was applied successfully in the determination of rutin in pharmaceutical preparations and monitoring the excretion of rutin in human urine.

A New Analytical Procedure for Assay of Lysozyme in Human Tear and Saliva with Immobilized Reagents in Flow Injection Chemiluminescence System

Analytical Sciences : the International Journal of the Japan Society for Analytical Chemistry. Mar, 2003  |  Pubmed ID: 12675337

A novel analytical procedure based on chemiluminescence (CL) detection was described for the determination of lysozyme at ng ml(-1) level by using controlled-reagent-release technology in a flow injection system. The analytical reagents involved in the CL reaction, including luminol and periodate, were both immobilized on the anion-exchange resins in the flow injection system. Through water injection, luminol and periodate were eluted from the anion-exchange column to generate the chemiluminescence, which was inhibited in the presence of lysozyme. By measuring the decrease of CL intensity, one could analyze the lysozyme quantitatively. The decrement of CL emission was linear over the logarithm of lysozyme concentration in the range of 30-1000 ng ml(-1). A typical analytical procedure, including sampling and washing, could be performed in 0.5 min at a flow rate of 2.0 ml min(-1), giving a throughput of 120 h(-1), with a relative standard deviation of less than 3.0%. The proposed method was applied successfully to the determination of lysozyme in human tear and saliva samples, and the recovery was from 92.0% to 105.7%.

A Study of the Chemiluminescence Behavior of Myoglobin with Luminol and Its Analytical Applications

Analytical and Bioanalytical Chemistry. Jan, 2004  |  Pubmed ID: 14663544

A chemiluminescence signal at 425 nm was observed when ferric state myoglobin was mixed with luminol in alkaline medium. Because the signal was remarkably enhanced in the presence of Fe(CN)6(4-), analytical applications were investigated in a flow-injection system. The increase in chemiluminescence was linearly dependent on myoglobin concentration in the range 0.1 to 100 nmol L(-1), and the limit of detection was 0.04 nmol L(-1) with relative standard deviation 3.2% (3 sigma). It was also found that binding of Mb with the ligands CN-, SCN-, and F- significantly inhibited the chemiluminescence reaction. The linear dynamic ranges for the ligands were 1.0-300.0, 0.1-3.0, and 0.5-100.0 nmol L(-1), and the limits of detection (S/N=3) 0.4, 0.04, and 0.2 nmol L(-1), for F-, CN-, and SCN-, respectively. The relative standard deviations were 5.32%, 6.13%, and 3.38% for 0.1 nmol L(-1) CN-, 0.5 nmol L(-1) SCN-, and 1.0 nmol L(-1) F-, respectively. At a flow rate of 2.0 mL min(-1) the assay could be accomplished in 1 min, including sampling and washing. The method has been successfully applied to the determination of myoglobin in human urine and F- in water samples. A possible mechanism of chemiluminescence production by myoglobin and luminol is presented.

Detection of Oncoprotein Platelet-derived Growth Factor Using a Fluorescent Signaling Complex of an Aptamer and TOTO

Analytical and Bioanalytical Chemistry. Mar, 2006  |  Pubmed ID: 16447044

There have recently been advances in the application of aptamers, a new class of nucleic acids that bind specifically with target proteins, as protein recognition probes for biomedical study. The development of a signaling aptamer with the capability of simple and rapid real-time detection of disease-related proteins has attracted increasing interest. We have recently reported a new protein-detection strategy using a signaling aptamer based on a DNA molecular light-switching complex, [Ru(phen)2(dppz)]2+. In this work we have used the commercially available DNA-intercalating dye, TOTO, to replace [Ru(phen)2(dppz)]2+ for detection of oncoprotein platelet-derived growth factor BB (PDGF-BB), a potential cancer marker. Taking advantage of the high affinity of the aptamer to PDGF-BB and the sensitive fluorescence change of the aptamer-TOTO signaling complex on protein binding, PDGF-BB was detected in physiological buffer with high selectivity and sensitivity. The detection limit was 0.1 nmol L(-1), which was better than that of other reported aptamer-based methods for PDGF-BB, including that using [Ru(phen)2(dppz)]2+. The method is very simple with no need for covalent labeling of the aptamer or probe synthesis. It facilitates wide application of the signaling mechanism to the analysis and study of cancer markers and other proteins.

A Hydrodynamically Focused Stream As a Dynamic Template for Site-specific Electrochemical Micropatterning of Conducting Polymers

Angewandte Chemie (International Ed. in English). 2008  |  Pubmed ID: 18176924

Seismic Damage Identification for Steel Structures Using Distributed Fiber Optics

Applied Optics. Aug, 2009  |  Pubmed ID: 19649054

A distributed fiber optic monitoring methodology based on optic time domain reflectometry technology is developed for seismic damage identification of steel structures. Epoxy with a strength closely associated to a specified structure damage state is used for bonding zigzagged configured optic fibers on the surfaces of the structure. Sensing the local deformation of the structure, the epoxy modulates the signal change within the optic fiber in response to the damage state of the structure. A monotonic loading test is conducted on a steel specimen installed with the proposed sensing system using selected epoxy that will crack at the designated strain level, which indicates the damage of the steel structure. Then, using the selected epoxy, a varying degree of cyclic loading amplitudes, which is associated with different damage states, is applied on a second specimen. The test results show that the specimen's damage can be identified by the optic sensors, and its maximum local deformation can be recorded by the sensing system; moreover, the damage evolution can also be identified.

Characterization of Reference Genes for Quantitative Real-time PCR Analysis in Various Tissues of Salvia Miltiorrhiza

Molecular Biology Reports. Jan, 2010  |  Pubmed ID: 19680786

Five reference genes, 18S, EF1alpha, alpha-Tubulin, Ubiquitin and Actin, from Salvia miltiorrhiza were analyzed as internal controls for gene expression profiling assay using quantitative real-time polymerase chain reaction (qRT-PCR). The five candidate genes were measured for their transcriptional level in seven tissues, including roots, stems, leaves, sepals, petals, stamens and pistils. Then they were ranked by the GeNorm tool. The results showed that Actin and Ubiquitin were the most stable whereas EF1alpha and 18S did not favor normalization of qRT-PCR results in these tissues. Expression levels of the SmDXR gene were studied in parallel, with Actin and Ubiquitin both or each as reference in the seven tissues, and varying relative quantifications of the SmDXR gene in seven tissues. This study indicated that selection of the most stable genes plays an important role in gene expression profiling assays.

A Microfluidic Platform for Systems Pathology: Multiparameter Single-cell Signaling Measurements of Clinical Brain Tumor Specimens

Cancer Research. Aug, 2010  |  Pubmed ID: 20631065

The clinical practice of oncology is being transformed by molecular diagnostics that will enable predictive and personalized medicine. Current technologies for quantitation of the cancer proteome are either qualitative (e.g., immunohistochemistry) or require large sample sizes (e.g., flow cytometry). Here, we report a microfluidic platform-microfluidic image cytometry (MIC)-capable of quantitative, single-cell proteomic analysis of multiple signaling molecules using only 1,000 to 2,800 cells. Using cultured cell lines, we show simultaneous measurement of four critical signaling proteins (EGFR, PTEN, phospho-Akt, and phospho-S6) within the oncogenic phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway. To show the clinical application of the MIC platform to solid tumors, we analyzed a panel of 19 human brain tumor biopsies, including glioblastomas. Our MIC measurements were validated by clinical immunohistochemistry and confirmed the striking intertumoral and intratumoral heterogeneity characteristic of glioblastoma. To interpret the multiparameter, single-cell MIC measurements, we adapted bioinformatic methods including self-organizing maps that stratify patients into clusters that predict tumor progression and patient survival. Together with bioinformatic analysis, the MIC platform represents a robust, enabling in vitro molecular diagnostic technology for systems pathology analysis and personalized medicine.

Quality Indicators for Acute Myocardial Infarction Care in China

International Journal for Quality in Health Care : Journal of the International Society for Quality in Health Care / ISQua. Aug, 2011  |  Pubmed ID: 21561980

Although quality indicators for the care of patients having acute myocardial infarction have been described for other countries, there are none specifically tailored to the Chinese health-care system. The study objective was to develop quality indicators for acute myocardial infarction in China, which measure and improve the quality of care for this patient population, and which could be reported on performance reports.

The Therapeutic Efficacy of Camptothecin-encapsulated Supramolecular Nanoparticles

Biomaterials. Feb, 2012  |  Pubmed ID: 22074663

Nanomaterials have been increasingly employed as drug(s)-incorporated vectors for drug delivery due to their potential of maximizing therapeutic efficacy while minimizing systemic side effects. However, there have been two main challenges for these vectors: (i) the existing synthetic approaches are cumbersome and incapable of achieving precise control of their structural properties, which will affect their biodistribution and therapeutic efficacies, and (ii) lack of an early checkpoint to quickly predict which drug(s)-incorporated vectors exhibit optimal therapeutic outcomes. In this work, we utilized a new rational developmental approach to rapidly screen nanoparticle (NP)-based cancer therapeutic agents containing a built-in companion diagnostic utility for optimal therapeutic efficacy. The approach leverages the advantages of a self-assembly synthetic method for preparation of two different sizes of drug-incorporated supramolecular nanoparticles (SNPs), and a positron emission tomography (PET) imaging-based biodistribution study to quickly evaluate the accumulation of SNPs at a tumor site in vivo and select the favorable SNPs for in vivo therapeutic study. Finally, the enhanced in vivo anti-tumor efficacy of the selected SNPs was validated by tumor reduction/inhibition studies. We foresee our rational developmental approach providing a general strategy in the search of optimal therapeutic agents among the diversity of NP-based therapeutic agents.