Tioxide Group Services Limited

Sapient Sensors Limited

Keith Robson

Leslie Ainsley Simpson

Ian Anthony Kinloch

David Trevor Knight

Stephen Lee Cash

Michael John Trendell

Peter George Stockley

Steven Hugh Ashdown

Martin R Davis

Stephen R Spruce

Kevin Drury

Ronald Brown

Lisa Blakey

Martin Alec Williamson

Daniel James Rutherford

A device for identifying the presence of a specific target molecule or biomarker by the detection of a change in an electrical property includes a measurement sensorcomprising a semiconducting sensor structurecapable of conjugating with the biomarker, thus giving rise to the said change in electrical property, and an electrode systemfor conducting a signal from the device. According to the invention there is a further such sensor, of substantially identical form but having its sensor structurealready conjugated with the biomarker, or otherwise capped, e.g. using a further oligonucleotide strand, so as to act as an internal reference. When a biological sample, e.g. saliva, is applied to the electrodes, the reference enables the discounting of all environmental effects other than the biomarker. The invention provides a simple, cheap and accurate test for one or more biomarkers that can be used in the field without complex equipment.

Device and method for biomarker detection

A device for identifying the presence of a specific target molecule or biomarker by the detection of a change in an electrical property includes a measurement sensorcomprising a semiconducting sensor structurecapable of conjugating with the biomarker, thus giving rise to the said change in electrical property, and an electrode systemfor conducting a signal from the device. According to the invention there is a further such sensor, of substantially identical form but having its sensor structurealready conjugated with the biomarker, or otherwise capped, e.g. using a further oligonucleotide strand, so as to act as an internal reference. When a biological sample, e.g. saliva, is applied to the electrodes, the reference enables the discounting of all environmental effects other than the biomarker. The invention provides a simple, cheap and accurate text for one or more biomarkers that can be used in the field without complex equipment.

Aptamer coated measurement and reference electrodes and methods using same for biomarker detection

An aqueous gloss emulsion paint comprises a dispersion of structured composite particles, said structured particles comprising an association of particles of inorganic pigment and polymeric particles. The polymeric particles are formed from a polymer or copolymer having a minimum film forming temperature not greater than 50.degree. C. The component particles of the composite particles are held in association as a result of surface charges on the particles said surface charges on the polymeric particles being of opposite sign to the surface charge on the particles of inorganic pigment. The ratio of polymeric particles to particles of inorganic pigment in the composite particles is from 0.5:1 to 6:1 by volume.

Gloss emulsion paints

A structured composite pigmentary material comprises composite particles consisting of an association of at least one titanium dioxide particle and at least one non-film-forming organic polymer particle wherein the particles are held in association as a result of a positive surface charge on the titanium dioxide particles and a negative surface charge on the polymeric particles, the composition of the composite being such that the ratio by volume of polymeric particles to titanium dioxide particles is in the range 0.3:1 to 0.6:1. An aqueous paint composition and a method of preparing the structured composite pigmentary material are described.

Composite pigmentary material

A process for preparing a structured composite pigmentary material comprises forming a dispersion of uncoated particles of titanium dioxide at a pH value at which the particles have a surface charge and subjecting the dispersion to cross-flow filtration until the dispersion contains more than 50% by weight titanium dioxide. The concentrated dispersion is mixed with a dispersion of chemically distinct particles having a surface charge of opposite sign under conditions which ensure that the sign of the surface charge on either of the particulate materials is not reversed. In the resultant composite pigmentary material the titanium dioxide particles are held in association with the chemically distinct particles as a result of said surface charges. The structured composite can be used to produce paints having higher opacity than conventional paints containing an equivalent amount of titanium dioxide and the durability of these paints is better than a conventional paint containing a similar amount of uncoated titanium dioxide.

A process for the production of a structured composite pigmentary material in the form of a dispersion comprises mixing an aqueous dispersion of inorganic pigmentary particles and an aqueous dispersion of polyvinyl chloride (PVC) particles. The inorganic pigment particles carry a positive surface charge and the PVC particles carry a negative surface charge and the particles in the composite are held in association as a result of these charges. The inorganic pigment particles and PVC particles are mixed in the presence of a surfactant system which provides both anionic and steric stabilisation. In one embodiment the surfactant system comprises a nonionic surfactant having an HLB value greater than 12 and at least 2% by weight of an anionic surfactant with respect to the weight of PVC particl In a second embodiment the surfactant system comprises at least 2% by weight (with respect to PVC) of one of more surfactants providing anionic and steric stabilisation and being ethylene oxide condensation products having a polyoxyethylene chain with an average length of at least 8 oxyethylene units. The product is useful in paints and provides improved opacity compared to conventional pigments and improved gloss compared to known structured composite pigments.

A novel method for the production of titanium dioxide slurries having a high solids content comprises subjecting an aqueous slurry of titanium dioxide to cross-flow filtration to produce a slurry containing at least 50%, preferably 60 to 80% titanium dioxide by weight. The slurry can be washed during filtration to reduce the concentration of soluble ions. The process can produce concentrated slurries of titanium dioxide having remarkably low viscosities.

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Durham, United Kingdom

Keith Robson