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A novel and rapid (45 min), quantitative chemiluminescence-based, surface immunoassay is reported for the detection of progesterone and œstriol in artificial saliva. The detection limits for these pregnancy hormones are 2.3 and 2.5 pg mL−1, respectively. The assay is based on the use of ferrocene-tagged, monoclonal antibodies immobilised on a surface, so that the oxidised ferricenium catalyses the reaction between luminol and hydrogen peroxide. The immunoassay is performed in negative, such that increasing the antigen concentration gives rise to decreasing light intensity that is observed, and is unaffected by antibody orientation on the surface. This affords a method of calibration that is readily translated to pregnancy hormone detection in a primary point-of-care environment. Biomolecules with similar structures to these pregnancy hormones found in saliva are demonstrated not to interfere with the immunoassay. [ABSTRACT FROM AUTHOR]

A microfluidic device has been developed to maintain viable heart tissue samples in a biomimetic microenvironment. This device allows rat or human heart tissue to be studied under pseudo in vivoconditions. Effluent levels of lactate dehydrogenase and hydrogen peroxide were used as markers of damaged tissue in combination with in situelectrochemical measurement of the release of reactive oxygen species (ROS). The parameters for perfusion were optimized to maintain biopsies of rat right ventricular or human right atrial tissue viable for up to 5 and 3.5 hours, respectively. Electrochemical assessment of the oxidation current of total ROS, employing cyclic voltammetry, gave results in real-time that were in good agreement to biochemical assessment using conventional, off-chip, commercial assays. This proof-of-principle, integrated microfluidic device, may be exploited in providing a platform technology for future cardiac research, offering an alternative approach for investigating heart pathophysiology and facilitating the development of new therapeutic strategies. [ABSTRACT FROM AUTHOR]

A mathematical model for a photosynthesis-inspired regenerative photogalvanic device, for transient rather than exclusively steady-state conditions, based on molecular electrochemistry rather than electron transfer processes involving semiconductors, is considered within this work and which is adapted from an experimental system previously developed (J. E. Halls and J. D. Wadhawan, Energy Environ. Sci., 2012, 5, 6541). Computational simulations suggest that pragmatically achievable systems behave as middle-of-the-range photo-rechargeable electrochemical capacitors for light-to-electrical energy storage; in contrast the system performance as a light-to-electrical energy convertor (viz., solar cell), for cells constructed from electrochemically reversible redox couples with fast photo-induced electron transfer reactions is critically dependent on the concentration of the supersensitiser; maximum power conversion efficiency of ca. 6.5% under 500 nm light, 2.4 mW cm(-2) intensity for typical experimental parameters, neglecting Ohmic losses, and employing galvanostatic discharge, with a power conversion efficiency that is capable of being increased by a factor of five (to ca. 34%) when the supersensitizer concentration increases by an order of magnitude (from 5.0 to 50.0 mM). Under an AM 2.0 solar spectrum, numerical simulations suggest that one potentially pragmatically achievable embodiment of this regenerative system is able to perform with a solar-to-electrical power conversion efficiency of 4.5% - an attractive realistic single cell value.

Electrochemical glycosylation of a selenoglycoside donor proceeds efficiently in an undivided cell in acetonitrile to yield beta-glycosides. Measurement of cyclic voltammograms for a selection of seleno-, thio-, and O-glycosides indicates the dependence of oxidation potential on the anomeric substituent allowing the possibility for the rapid construction of oligosaccharides by selective electrochemical activation utilising variable cell potentials in combination with reactivity tuning of the glycosyl donor. A variety of disaccharides are readily synthesised in high yield, but limitations of the use of selenoglycosides as glycosyl donors for selective glycosylation of thioglycoside acceptors are exposed. The first electrochemical trisaccharide synthesis is described.

A series of six chalcoglycosides (phenyl-2,3,4,6-tetra-O-benzoyl-1-seleno-beta-D-glucopyranoside, phenyl-2,3,4,6-tetra-O-benzyl-1-seleno-beta-D-glucopyranoside, phenyl-2,3,4,6-tetra-O-benzyl-1-thio-beta-D-glucopyranoside, p-tolyl-2,3,4,6-O-benzoyl-1-thio-beta-D-glucopyranoside, p-tolyl-2,3,4,6-O-benzyl-1-thio-beta-D-glucopyranoside, and phenyl-2,3,4,6-O-benzyl-beta-D-glucopyranoside) are voltammetrically interrogated in dimethyl sulfoxide, so as to determine their formal (i.e. thermodynamic) redox potentials. The electrochemical oxidation of the chalcoglycoside is shown to follow an overall EC-type mechanism, in which the electro-generated cation radical undergoes an irreversible carbon-chalcogen bond rupture to produce the corresponding glycosyl cation, which may react further. The kinetics of the initial heterogeneous electron transfer process and subsequent irreversible homogeneous chemical degradation of the radical cation are reported, with values for the standard electrochemical rate constant k(0) in the order of 10(-2) cm s(-1) and the first order homogeneous rate constant, k(1), of the order of 10(3) s(-1). The formal oxidation potentials were found to vary according to the identity of the chalcogenide, such that OPh > SPh similar to STol > SePh.