Abstract: Chemical reactions occurring within a living cell are measured in a manner that does not affect the viability of the cell or the reaction under study. In one embodiment, one or more sensors are introduced into the cell and/or covalently associated with the exterior cell membrane. The sensor(s) emit an observable signal indicating a value of a parameter associated with the chemical reaction, e.g., the concentration of a reaction product. Because cell viability is not compromised, the cell may be stimulated (e.g., by subjection to an agonist or antagonist, a pathogen, a pharmaceutical compound, or a potential toxin) so as to affect the reaction under study.

Abstract: The systems and methods disclosed herein include a sensor particle for detecting the presence of a chelatable analyte, such as glucose, wherein the sensor comprises a chromophore and a fluorescent component, such as a quantum dot. The sensor particle further comprises moieties that bind both a clelatable analyte and chromophore reversibly and competitively. In the presence of the chelatable analyte, the moieties bind the analyte, and release the chromophore. The chromophore absorbs photons of one wavelength in a free state but of a different wavelength in a bound state, and is selected to operate with the fluorescent component such that the chromophore absorbs emissions of the fluorescent substance in only one of the bound and unbound states. In certain aspects, the invention comprises methods for detecting the presence of a chelatable analyte in a medium such as water, blood plasma and urine, using the sensor particles of the invention.

Abstract: The invention provides ion-selective sensors capable of selectively measuring ions, e.g., Na+, K+, Cl?, etc., in the cytosol of a single living cell. The sensor comprises one or more quantum dots or a fluorescent dye, a pH-sensitive dye, and optionally an ion-selective component such as an ionophore. These elements may, for example, be disposed in a polymer matrix. The polymer matrix comprises an internalizing moiety which enables the sensor to localize within the cytosol of a cell. The internalizing moiety comprises a small molecule or peptide such as an amine, antepennepedia, mastoparan, or melittin that react under acidic conditions to release a sensor from the confines of a endosome. Once in the cytosol the sensors may detect ionic analytes by selective ion extraction by the polymer, thereby inducing a pH change within the sensor which in turn changes the absorbance of the pH-sensitive dye. The change of absorbance may in turn attenuate the intensity of detectable emissions, e.g.

Abstract: The invention provides ion-selective sensors comprising quantum dots capable of selectively measuring ions, e.g., Na+, K+, Cl?, etc., in various environments, including in the cytosol of a living cell. Quantum dots are attractive probes for microscopy due to their photophysical advantages over fluorescent dyes, including prolonged photostability, brightness and quantum efficiency. In certain embodiments, a sensor comprises one or more quantum dots, a pH-sensitive dye, and optionally an ion-selective component such as an ionophore. These elements may, for example, be disposed in a polymer matrix. In certain embodiments, the sensors may detect ionic analytes by selective ion extraction by the polymer, thereby inducing a pH change within the sensor which in turn changes the absorbance of the pH-sensitive dye. The change of absorbance may in turn attenuate the intensity of detectable emissions, e.g., fluorescence, from the quantum dot by directly absorbing its fluorescence emission.

Abstract: Systems and methods are provided for optically measuring ion concentrations in biological samples. The systems and methods employ polymer-based optical ion sensors that include ion-selective ionophores and a pH sensitive chromionophore. Electrodes are providing for electrically stimulating the biological samples.

Abstract: Optical fiber sensors and fiberless optical sensors for measuring analytes, and in particular nitric oxide, are described utilizing metals, and more particularly, metal colloids. Proteins (or fragments thereof) with selective binding are immobilized on metal particles. The proteins may be dye-labeled for increased sensitivity.

Abstract: Optical fiber sensors and fiberless optical sensors for measuring analytes, and in particular nitric oxide, are described utilizing metals, and more particularly, metal colloids. Proteins (or fragments thereof) with selective binding are immobilized on metal particles. The proteins may be dye-labeled for increased sensitivity.

Abstract: Optical fiber sensors and fiberless optical sensors for measuring analytes, and in particular nitric oxide, are described utilizing metals, and more particularly, metal colloids. Proteins (or fragments thereof) with selective binding are immobilized on metal particles. The proteins may be dye-labeled for increased sensitivity. Additionally, metals functionally linked to reporter dyes are described in addition to the incorporation of reference compounds for ratiometric measurements.

Abstract: Fiberless optical sensors (plasticized PVC, acrylamide or gold particles) are described having a size ranging from between approximately 1 micrometer and 1 nanometer in diameter. The sensors comprise ionophores useful for the detection of intracellular analytes.

Abstract: Fiberless optical sensors (plasticized PVC, acrylamide or gold particles) are described having a size ranging from between approximately 1 micrometer and 1 nanometer in diameter. The sensors comprise ionophores useful for the detection of intracellular analytes.

Abstract: Fiber-optic sensors and fiberless sensors are made for measuring analytes, in particular nitric oxide. The sensors contain a compound specific for the analyte such a nitric oxide-binding compound. Fiber-optic sensors contain the compound immobilized on the tip of the fiber. The tip may be coated with an inert coating such as a metal layer and the compound is immobilized on the coating. Nitric oxide-binding compounds include heme-binding proteins, porphyrin group-containing proteins, heme group-containing proteins, dye-labeled porphyrin group-containing proteins and dye-labeled heme group-containing proteins. In a specific embodiment, dye-labeled cytochrome c′ such as fluorescein-labeled cytochrome c′ is immobilized on a fiber tip containing a gold colloid layer. The fiberless sensors are small enough to enter a single mammalian cell relatively non-invasively.

Abstract: Fiberless optical sensors (plasticized PVC, acrylamide or gold particles) are described having a size ranging from between approximately 1 micrometer and 1 nanometer in diameter. The sensors comprise ionophores useful for the detection of intracellular analytes.

Abstract: Optical fiber sensors and fiberless optical sensors for measuring analytes, and in particular nitric oxide, are described utilizing metals, and more particularly, metal colloids. Proteins (or fragments thereof) with selective binding are immobilized on metal particles. The proteins may be dye-labeled for increased sensitivity.