Abstract: A computer aided rational molecular design method that includes establishing a virtual library of functional monomers each having a portion that is capable of polymerizing and a functional group that is capable of interacting with a template molecule with the aid of a computer, designing a molecular model of a biological template molecule by a computer facilitated molecular mechanical method and screening said virtual library of functional monomers and selecting those monomers which have the highest binding score to the template molecule by their functional group.

Abstract: Reaction of a dialdehyde, particularly phthaldialdehyde (I), with R—Z where Z is a nucleophilic group (preferably SH) and R is polymerisable (e.g. allyl) gives a reactive thioacetal (V) which can react with an amine ligand L—NH2 to produce an isoindole (IV) which may be fluorescent. At some stage, generally before interaction with L—NH2, the R groups are polymerised, possibly leading to self-assembly of the polymer on a metal or SH-bearing surface. Such a coated surface is useful as a transducer in assays or as a binding medium e.g. for chromatography.

Abstract: To facilitate preparation of a molecularly imprinted polymer (MIP) which specifically binds a particular template substance, a virtual library of functional monomers is screened to find those that interact strongly with a molecular model of the substance. A selected few are then “annealed” with the substance in a computer simulation. This shows the optimum ratios of template substance to individual monomers. An appropriate mixture of monomers is then polymerised in the presence of the template to produce a MIP.

Abstract: A method of determining an analyte in the gaseous or vapour phase and in which a bioreceptor or biomimic is retained at an electrode. The bioreceptor or biomimic is preferably retained at a support at the electrode which comprises a solid or gel matrix of an electrolyte, especially organic salt electrolytes. Electrochemical detection of analytes in this way has several advantages over existing methods which rely on solution monitoring. For example gas sensors can be prepared for monitoring an analyte by the occurrence of a reaction with a bioreceptor or biomimic, in addition to monitoring the presence of toxins due to inhibition of the bioreceptor or biomimic reaction. Furthermore, the invention enables gas or vapour analyte monitoring with increased sensitivity and speed and greater stability of the sensors can be achieved. The invention also relates to novel media for carrying out bioelectrochemical reactions.

Abstract: A sensor is provided which is sensitive to a particular property of a medium and which is thermally activated when in contact with the property containing medium. The sensor is externally mounted on the undersurface of a silicon wafer, the upper surface of which contains a well in which a vibratile bridge element is located. The top of the well is closed off so that the vibratile bridge element is within a chamber. Excitation energy from a source is delivered to the vibratile bridge element to establish vibratory motion which is monitored and detected by a circuit. Presence of the particular property in the medium causes a thermal change in the wafer resulting in a change in the resonance frequency of the vibratory motion of the vibratile bridge element. The frequency shift is a measure of the particular property.

Abstract: A method of determining an analyte in an organic or microaqueous solution involves the use of an enzyme electrode at which an enzyme is retained. The enzyme may be immobilised covalently at the electrode but is preferably retained at a hydrophilic support (4) which may be connected to an electrical conductor. Electrochemical detection of analytes in organic or microaqueous solvents using an enzyme electrode has several advantages over existing methods which employ aqueous solutions of analyte. For example compounds with low water solubilities may be detected, detection of a particular analyte may be made more selective by appropriate choice of solvent, the thermal stability of the enzyme may be enhanced and the enzymes may be readily retained at the electrode by virtue of their insolubility in the organic or microaqueous solvent.

Abstract: Microbial activity in an aqueous medium is measured in a bioelectrochemical cell in which the working electrode comprises an electrically conductive carbon-bearing porous material; suitably a graphitized carbon felt or cloth. This enhances the BEC response by increasing the surface area and by absorbing microbes onto the surface; and the electrode material can also be used to preconcentrate the microbes prior to use as an electrode in the cell.

Abstract: 1,4-Benzoquinone can act as a mediator of electron transfer in bioelectrochemical cells for measuring microbiological activity in a sample. In combination with ferricyanide it can provide a surprisingly high level of mediator activity with many microorganisms, and a more even response when the sample may contain a mixture of microorganisms.

Abstract: Bioelectrochemical processes use tetrathiafulvalenes (TTF) as a mediator of electron transfer between biological systems and electrodes. Typically it finds use in bioelectrochemical assays, e.g. involving glucose oxidase mediated oxidation of glucose. The TTF may be immobilized on the electrode surface, as may one or more enzymes involved in the process.