carbocyanines and Diabetes-Mellitus

A novel fluorescent turn-on probe (HCyHP) was developed in a simple two-step synthesis for monitoring of exogenous and endogenous H2O2 levels in biological samples and hypoxic cancer diagnosis.

Topics: Animals; Blood Glucose; Blood Glucose Self-Monitoring; Carbocyanines; Carbon-13 Magnetic Resonance Spectroscopy; Cell Hypoxia; Diabetes Mellitus; Early Detection of Cancer; Fluorescent Dyes; HeLa Cells; Heterografts; Humans; Hydrogen Peroxide; Light; Mass Spectrometry; Mice; Molecular Imaging; Neoplasms; Proton Magnetic Resonance Spectroscopy

We selected and modified DNA aptamers specifically bound glycated human serum albumin (GHSA), which is an intermediate marker for diabetes mellitus. Our aptamer truncation study indicated that the hairpin-loop structure with 23 nucleotides length containing triple G-C hairpins and 15-nucleotide loop, plays an important role in GHSA binding. Fluorescent quenching graphene oxide (GO) and Cy5-labeled G8 aptamer were used in this study to develop simple and sensitive graphene based aptasensor for GHSA detection. The limit of detection (LOD) of our aptasensor was 50 μg/mL, which was lower than other existing methods. In addition, with the nuclease resistance system, our GHSA detection platform could also be used in clinical samples. Importantly, our approach could significantly reveal the higher levels of GHSA concentrations in diabetes than normal serums. These indicate that our aptasensor has a potential for diagnosis and monitoring of diabetes mellitus.

Topics: Aptamers, Nucleotide; Base Sequence; Biosensing Techniques; Carbocyanines; Diabetes Mellitus; Fluorescent Dyes; Glycated Serum Albumin; Glycation End Products, Advanced; Graphite; Humans; Limit of Detection; Oxides; Serum Albumin

The identification of a beta-cell tracer is a major quest in diabetes research. However, since MRI, PET and SPECT cannot resolve individual islets, optical techniques are required to assess the specificity of these tracers. We propose to combine Optical Coherence Microscopy (OCM) with fluorescence detection in a single optical platform to facilitate these initial screening steps from cell culture up to living rodents. OCM can image islets and vascularization without any labeling. Thereby, it alleviates the need of both genetically modified mice to detect islets and injection of external dye to reveal vascularization. We characterized Cy5.5-exendin-3, an agonist of glucagon-like peptide 1 receptor (GLP1R), for which other imaging modalities have been used and can serve as a reference. Cultured cells transfected with GLP1R and incubated with Cy5.5-exendin-3 show full tracer internalization. We determined that a dose of 1 μg of Cy5.5-exendin-3 is sufficient to optically detect in vivo the tracer in islets with a high specificity. In a next step, time-lapse OCM imaging was used to monitor the rapid and specific tracer accumulation in murine islets and its persistence over hours. This optical platform represents a versatile toolbox for selecting beta-cell specific markers for diabetes research and future clinical diagnosis.

Topics: Animals; Carbocyanines; Cell Line; Cricetulus; Diabetes Mellitus; Female; Fluorescent Dyes; Glucagon-Like Peptide-1 Receptor; Insulin-Secreting Cells; Mice; Mice, Inbred ICR; Peptides; Tomography, Optical Coherence

This study aimed to investigate the membrane potential and fluidity changes of human red blood cells subjected to isotonic glucose solutions. For the control erythrocytes a membrane potential value of -10.1 +/- 1.8 mV was obtained, whereas erythrocyte membranes in diabetic cells were hyperpolarized, with a potential of -13.9 +/- 2.3 mV. Incubation of both types of red blood cells with increasing glucose concentrations resulted in a substantial hyperpolarization of the cell membranes. Glucose solutions in water had a much stronger effect on membrane potential than glucose dissolved in phosphate-buffered saline. Red blood cell membrane fluidity measurements using the fluorescent label TMADPH did not reveal any significant changes upon incubation with glucose.

Topics: Benzothiazoles; Carbocyanines; Diabetes Mellitus; Diphenylhexatriene; Erythrocyte Membrane; Fluorescent Dyes; Glucose; Humans; Isotonic Solutions; Membrane Fluidity; Membrane Potentials