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Using the self-assembly of aromatic boronic acids with Alizarin Red S (ARS), we developed a new chemosensor for the selective detection of peroxynitrite., Using the self-assembly of aromatic boronic acids with Alizarin Red S (ARS), we developed a new chemosensor for the selective detection of peroxynitrite. Phenylboronic acid (PBA), benzoboroxole (BBA) and 2-(N,N-dimethylaminomethyl)phenylboronic acid (NBA) were employed to bind with ARS to form the complex probes. In particular, the ARS–NBA system with a high binding affinity can preferably react with peroxynitrite over hydrogen peroxide and other ROS/RNS due to the protection of the boron via the solvent-insertion B–N interaction. Our simple system produces a visible colorimetric change and on–off fluorescence response towards peroxynitrite. By coupling a chemical reaction that leads to an indicator displacement, we have developed a new sensing strategy, referred to herein as RIA (Reaction-based Indicator displacement Assay).

We demonstrate a novel field-effect saccharide sensor device using an AlGaN/GaN heterostructure functionalized with a chemical receptor, featuring a thiol group, alkane chain linker and a simple boronic acid. Fabricated devices were demonstrated to electronically detect buffered saccharide solutions (fructose, galactose and glucose) of varying concentrations. These results provide proof-of-concept for the development AlGaN/GaN-based sensor devices incorporating boronic acid receptor chemistry.

Fluorescein isothiocyanate is treated with 3-aminophenylboronic acid to provide a fluorescently tagged boronic acid derivative which is used to assess Förster resonance energy transfer (FRET) quenching upon boronate ester formation with a series of bespoke diol appended quenchers. Fluorescence spectroscopy comparison of quenching efficiency between treatment of fluorescein and its boronic acid appended congener with quencher appended diol reveals boronate ester formation (covalently linked) to be the more efficient regime and from the panel of quenchers which also included nucleosides.

This communication describes the synthesis of an electrochemically active oligonucleotide probe and its application in sensing complementary oligonucleotides sequences using a T7 exonuclease enzyme. Target oligonucleotides are detected by hybridisation with a ferrocene labelled probe oligonucleotide followed by addition of T7 exonuclease. The T7 enzyme is a double strand specific exonuclease that removes the terminal 5′ nucleotide of the probe sequence. The 5′ nucleotide is attached to a ferrocene label, which is subsequently detected at an electrode using differential pulse voltammetry. Time and temperature resolved measurements were performed and an associated study using dual labelled fluorophore–quencher labelled probes was performed to confirm the validity of the electrochemical assay. Keywords: DNA, Electrochemistry, T7 exonuclease

Palladium catalysed, aryl boronic acid homocoupling, is explored as a fluorescence sensing regime for saccharides. The catalytic formation rate of fluorescent bi-aryls, under control of a palladium catalyst, is modulated by the presence of saccharides. The nature of the aryl group, rate of biaryl formation and limits of detection are investigated.

A simple three step synthesis was developed to provide six novel modular sensors, consisting of three para sensors, and three meta sensors with naphthalene, anthracene and pyrene fluorophores. The interaction of the six sensors with the saccharides: D-glucose, D-fructose, D-galactose, and D-mannose, were evaluated. All sensors displayed increasing fluorescence intensity upon the addition of these saccharides, with all of the sensors showing enhanced selectivity for D-glucose over D-galactose, D-fructose and D-mannose. High affinity (Kobs) was also observed for the meta sensors with respect to the para sensors. The naphthalene and anthracene meta sensors showed particularly high affinity (Kobs) for D-galactose. Circular dichroism spectroscopy was used to probe the structures of the complexes formed. Cyclic complexes were formed between all six sensors and D-glucose. Whilst naphthalene and anthracene meta sensors which displayed high affinity for D-galactose also formed cyclic complexes with that saccharide.