boron and pyrene

This paper presents a graphene nanosensor for affinity-based detection of low-charge, low-molecular-weight molecules, using glucose as a representative. The sensor is capable of measuring glucose concentration in a practically relevant range of 2 μM to 25 mM, and can potentially be used in noninvasive glucose monitoring.

Topics: Biosensing Techniques; Boron; Boronic Acids; Electrodes; Equipment Design; Esters; Glucose; Graphite; Humans; Hydrogen-Ion Concentration; Molecular Weight; Nanoparticles; Nanotechnology; Pyrenes; Silver; Silver Compounds

Four-channel fluorescence assay toward six monosaccharides was achieved by employing two novel pyrene-functionalized boronlectins with flexible diboronic acid as receptors. The effects of pH values and aging time on the sensor properties were thoroughly evaluated by UV-vis, fluorescence spectroscopy and dynamic light scattering. We find that the fluorescence relative ratios were highly correlated with analyte concentrations at μM level. The flexibility of the receptors was perceived as an indispensable factor to produce diverse fluorescence signals toward different monosaccharides. Most importantly, integration of four fluorescence channels derived from the two sensors enables an excellent discrimination for all tested monosaccharides at a certain concentration or a concentration range via linear discriminant analysis (LDA). It is proposed that the multiple flexible linkers in the boronlectins could increase their self-adaptive capacity for different analytes, and facilitate the formation of stable boronlectin-sugar aggregate assemblies. In addition, practical sensing of glucose in the simulative blood and urine was illustrated to be feasible in the presence of interferences at physiological concentrations.

Topics: Boron; Lectins; Monosaccharides; Pyrenes; Sensitivity and Specificity; Spectrometry, Fluorescence

We report on the formation of monomolecular layers of perylene- and pyrene-alkanoic acids on boron-doped diamond (BDD) substrates. The carboxylic acid layers are bound by coordination to zirconium phosphate (ZP) functionalities on the BDD substrate surface. The resulting Zr-phosphate-carbonate (ZPC) linkages between the substrate and the adlayer are asymmetric, of the form -(OPO3(2-) Zr4+-O2C-R)+ X-. Pyrene and perylene are well-established optical probes of polarity and viscosity at interfaces. We have used electrochemical and steady-state fluorescence techniques to study the loading density and behavior of these monomolecular films, allowing comparison of BDD and indium-doped tin oxide (ITO) substrates. Electrochemical data suggest that the pyrene chromophores are positioned roughly at the same distance from the surface, regardless of the length of the anchoring alkanoic acid chain, a finding that can be explained by the pyrene lying on the substrate surface. Such a conformation is plausible given the surface coverage (5 x 10(-11) mol/cm2, ca. 0.1 monolayer) we measure for these systems.

Topics: Boron; Carbonates; Diamond; Electrochemistry; Optics and Photonics; Perylene; Pyrenes; Sensitivity and Specificity; Spectrum Analysis; Surface Properties; Zirconium