tellurium and Diabetes-Mellitus

Bioorthogonal chemistry has been considered as a powerful tool for biomolecule labeling due to its site specificity, moderate reaction conditions, high yield, and simple post-treatment. Covalent coupling is commonly used to modify quantum dots (QDs) with bioorthogonal functional group (azide or cycloalkyne), but it has a negative effect in the decrease of QDs' quantum yield and stability and increase of QDs' hydrodynamic diameter. To overcome these disadvantages, we propose a novel method for the preparation of two kinds of clickable QDs by the strong interaction of -SH with metal ions. One system involves azide-DNA-functionalized QDs, which are used for bioconjugation with dibenzocyclooctyne (DBCO)-modified glucose oxidase (GOx) to form a GOx-QDs complex. After bioconjugation, the stability of QDs was improved, and the activity of GOx was also enhanced. The GOx-QDs complex was used for rapid detection of blood glucose by spectroscopy, naked eye, and paper-based analytical devices. The second system involves DBCO-DNA-functionalized QDs, which are used for an in situ bioorthogonal labeling of HeLa cells through metabolic oligosaccharide engineering. Therefore, these clickable QDs based on DNA functionalization can be applied for rapid and effective labeling of biomolecules of interest.

Topics: Biosensing Techniques; Blood Glucose; Cadmium Compounds; Diabetes Mellitus; Glucose; HeLa Cells; Humans; Quantum Dots; Tellurium; Zinc

A simple and sensitive inner filter effect and charge transfer dual response ratiometric fluorescent probe (D-RFP) for sensing glucose was developed based on etching of silver nanoprisms (Ag NPRs). The D-RFP was proposed by hybridizing red emitting CdTe QDs and blue emitting CDs into core-shell structured silica nanoparticles. In this design, when mixed Ag NPRs with the D-RFP, QDs which embedded in silica nanoparticles can be quenched by Ag NPRs via inner filter effect. Ag NPRs can be effectively etched to silver ions by H

Topics: Cadmium Compounds; Carbon; Color; Colorimetry; Diabetes Mellitus; Fluorescence; Fluorescent Dyes; Glucose; Glucose Oxidase; Humans; Hydrogen Peroxide; Limit of Detection; Oxidation-Reduction; Quantum Dots; Silicon Dioxide; Silver; Tellurium

To evaluate the impact of diabetes mellitus (DM) on the accuracy of myocardial perfusion scintigraphy (MPS) in detecting coronary artery disease (CAD).. Two hundred and sixteen patients with DM and 432 matched controls were submitted to MPS on a dedicated cardiac camera equipped with cadmium-zinc-telluride (CZT) detectors and coronary angiography. Exercise stress was performed in 442 (68%) patients, while the remainders underwent vasodilator stress. Exercise level was determined as the percentage of the predicted maximal workload that was attained (%Wattmax). The summed difference score was derived from CZT images. A coronary stenosis >70% was considered obstructive. The prevalence of obstructive CAD was 59.7% in patients with DM and 56.2% in controls (P = NS). The accuracy of MPS in detecting CAD was similar in patients with and without DM [area under the ROC curve (AUC) 0.77 vs. 0.78, P = NS]. An interaction between the accuracy of MPS and cardiac stress-protocol was revealed. In fact, in patients with DM exercise stress CZT had a lower accuracy than vasodilator-stress (AUC 0.70 vs. 0.89, P < 0.001), because of a lower specificity (45% vs. 69%), while in the control group the accuracy of MPS was similar regardless of the stress-protocol adopted. Patients with DM attained a significantly lower %Wattmax during exercise than controls (76 ± 27% vs. 82 ± 26%, P = 0.038), which resulted an independent predictor of reduced specificity (P = 0.026).. The accuracy of CZT imaging in patients with DM is elevated, and it is quite comparable to the one obtained in patients without DM. However, a reduced specificity can be expected in the case of exercise stress CZT, because of an impaired exercise capacity.

Topics: Aged; Aged, 80 and over; Cadmium; Case-Control Studies; Coronary Angiography; Coronary Stenosis; Diabetes Mellitus; Exercise Test; Female; Follow-Up Studies; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Radiographic Image Enhancement; Reference Values; Retrospective Studies; Risk Assessment; Sensitivity and Specificity; Tellurium; Tomography, Emission-Computed, Single-Photon; Video Recording; Zinc

Highly luminescent water soluble CdTe quantum dots (QDs) were synthesized and conjugated with anti-HbA1c antibody to generate specific nanobioprobe. A sandwich immunoassay model was employed using capture HbA1c antibody as a specific receptor molecule and the QD-labeled secondary antibody as a dual (fluorescence cum electrochemical) tracer to quantify the concentration of HbA1c. A linear increase in current was observed for HbA1c analytical standards with a R(2) value of 0.990 and coefficient of variance ~5%. A comparison between HPLC and dual immunoassay for clinical samples showed a correlation coefficient of 89% and 96% for fluorescence and electrochemical detection methods respectively. The QD-based immunoassay shows great promise for rapid reproducible and cost effective analysis of HbA1c in clinical samples.

Topics: Adult; Biomarkers; Cadmium Compounds; Diabetes Mellitus; Electrochemical Techniques; Glycated Hemoglobin; Humans; Immunoassay; Immunoconjugates; Luminescent Agents; Quantum Dots; Sensitivity and Specificity; Spectrometry, Fluorescence; Tellurium

A novel label-free detection system based on CdTe/CdS quantum dots (QDs) was designed for the direct measurement of glucose. Herein we demonstrated that the photoluminescence (PL) of CdTe/CdS QDs was sensitive to hydrogen peroxide (H(2)O(2)). With d-glucose as a substrate, H(2)O(2) that intensively quenched the QDs PL can be produced via the catalysis of glucose oxidase (GOx). Experimental results showed that the decrease of the QDs PL was proportional to the concentration of glucose within the range of 1.8 microM to 1mM with the detection limit of 1.8 microM under the optimized experimental conditions. In addition, the QD-based label-free glucose sensing platform was adapted to 96-well plates for fluorescent assay, enhancing the capabilities and conveniences of this detection platform. An excellent response to the concentrations of glucose was found within the range of 2-30 mM. Glucose in blood and urine samples was effectively detected via this strategy. The comparison with commercialized glucose meter indicated that this proposed glucose assay system is not only simple, sensitive, but also reliable and suitable for practical application. The high sensitivity, versatility, portability, high-throughput and low cost of this glucose sensor implied its potential in point-of-care clinical diagnose of diabetes and other fields.

Topics: Blood Glucose; Cadmium; Diabetes Mellitus; Glucose; Glucose Oxidase; Glycosuria; Humans; Hydrogen Peroxide; Luminescent Measurements; Point-of-Care Systems; Quantum Dots; Tellurium