Abstract: Methods and devices for the detection and identification in a sample of one or more target molecules which bind to nucleic acid probe molecules are provided. The method includes contacting the sample with a surface that is coated with one or more gradients of nucleic acid or nucleic acid analog probe molecules that bind target molecules in the sample. Gradients are formed by varying a physical, structural or functional property of the probes on the surface; for example, the density of probe molecules bound to the surface. The coating layer or immobilization layer in which the gradient is formed is preferably continuous Determination of the location, speed and/or extent of hybridisation of a nucleic acid on a gradient surface is useful to identify target molecules bound to probes and/or to quantitatively measure the amount of the target in a sample.

Abstract: A biosensor for direct analysis of nucleic acid hybridization by use of an optical fiber functionalized with nucleic acid molecules and fluorescence transduction is disclosed. Nucleic acid probes are immobilized onto the surface of optical fibers and undergo hybridization with complementary nucleic acids introduced into the local environment of the sensor. Hybridization events are detected by the use of fluorescent compounds which bind into nucleic acid hybrids. The invention finds uses in detection and screening of genetic disorders, viruses, and pathogenic microorganisms. Biotechnology applications include monitoring of gene cultures and gene expression and the effectiveness (e.g. dose-response) of gene therapy pharmaceuticals. The invention includes biosensor systems in which fluorescent molecules are connected to the immobilized nucleic acid molecules. The preferred method for immobilization of nucleic acids is by in-situ solid phase nucleic acid synthesis.

Abstract: The invention provides improved methods and devices for the detection and identification in a sample of one or more target molecules which bind to probe molecules, particularly to nucleic acid probe molecules. The improved method is based on contacting the sample with a surface that is coated with one or more gradients of probe molecules, particlarly nucleic acid or nucleic acid analog probe molecules that serve to bind target molecules in the sample, particularly nucleic acids having sequences that are complementary or partially complementary to one or more probe molecules. A probe gradient generated on the surface is formed by the variation of a physical, structural or functional property of the probes on the surface. The gradient is generated, e.g.

Abstract: A biosensor for direct analysis of nucleic acid hybridazation by use of an optical fiber functionalized with nucleic acid molecules and fluorescence transduction is disclosed. Nucleic acid probes are immobilized onto the surface of optical fibers and undergo hybridization with complementary nucleic acids introduced into the local environment of the sensor. Hybridization events are detected by the use of fluorescent compounds which bind into nucleic acid hybrids. The invention finds uses in detection and screening of genetic disorders, viruses, and pathogenic micoorganisms. Biotechnology applications include monitoring of gene cultures and gene expression and the effectiveness (e.g. dose-response) of gene therapy pharmaceuticals. The invention includes biosensor systems in which fluorescent molecules are connected to the immobilized nucleic acid molecules. The preferred method for immobilization of nucleic acids is by in situ solid phase nucleic acid synthesis.

Abstract: The invention provides methods for conducting hybridizations having increased selectivity of hybridization using substrates upon which probe nucleic acids are immobilized. The methods of this invention can be used to increase selectivity in nucleic acid diagnostic devices, such as biosensors and microarrays. The invention provides increased selectivity through control of the substrate surface chemistry and in particular, through control of the density of nucleic acids and other oligomers immobilized on a surface. The invention provides improved signal to noise in hybridization assays via enhanced differences in signal magnitude generated for fully matched target nucleic acid compared to partially matched target nucleic acid prior to signal processing.

Abstract: A novel optical chemical sensor for direct and continuous detection of organic species in process streams is described. The sensor is based on the use of surface plasmon resonance to amplify fluorescence emission from chemically selective membranes which can be deposited as Lang-muir-Blodgett films on thin metal island films.

Abstract: A lipid membrane is used as a chemo-receptive transducer for quantitative and semi-quantitative analysis of chemical test species in an electrolyte. The lipid membrane is contacted with an electrolyte containing the test species, and an electrical potential difference is applied across the membrane. From measurements of the trans-membrane ion current variation due to the presence of the test species, a quantitative analysis of the test species may be conducted, on a highly selective basis. Receptors showing a high degree of selectiveity towards the species are included in the membrane.

Abstract: A protected, lipid membrane-based device useful as a chemoreceptive transducer is provided. The device includes a porous, membrane-protective layer attached to an underlying, lipid membrane. Also provided is a process for using the protected device to determine the concentration of a specified chemical species.There is additionally provided a lipid membrane-based gas sensor. The sensor includes a gas-permeable, hydrated upper layer attached to an underlying lipid membrane. Furthermore, the invention includes a process for using the gas sensor to determine the concentration of an inorganic ion formed from an inorganic ion-forming gas.

Abstract: A lipid membrane is used as a chemo-receptive transducer for quantitative and semi-quantitative analysis of chemical test species in an electrolyte. The lipid membrane is contacted with an electrolyte containing the test species, and an electrical potential difference is applied across the membrane. From measurements of the trans-membrane ion current variation due to the presence of the test species, a quantitative analysis of the test species may be conducted, on a highly selective basis. Receptors showing a high degree of selectivity towards the test species are included in the membrane.

Abstract: A stabilized, lipid membrane-based device is provided. This device includes a plurality of membrane-forming lipids, and a support for stabilizing the lipid membrane. Each membrane-forming lipid includes a long chain through which the lipid is anchored to a binding site on the support, and another long chain unattached to the support. The support binding sites are spaced apart from one another to provide the lipid membrane with an appropriate molecular packing density.Also provided is a process for determining the concentration of a selected chemical species in an aqueous electrolytic solution, using an electrochemical cell formed from a lipid membrane-based device in accordance with the present invention. This process includes the step of applying across the lipid membrane of the device an electrical potential difference to produce an analytical signal based upon an increase in membrane ion permeability.