Abstract: A microfluidic pH-stat with a specially-is designed slide and portable device can be used for point-of-care enzyme diagnostics. The slide includes a microchamber and a substrate for the enzyme being tested. The substrate is homogenized with the sample in the microchamber to form a test volume. The microchamber includes a working microelectrode that injects current to split water in the test volume to generate hydrogen ions and/or hydroxide ions and a micro-pH-electrode to measure a pH of the test volume; the slide also includes a reference microelectrode. The device includes a processor to adjust the injected current based on the pH of the test volume and determine an activity of the enzyme based on an amount the injected current is adjusted.

Abstract: A microfluidic pH-stat with a specially-is designed slide and portable device can be used for point-of-care enzyme diagnostics. The slide includes a microchamber and a substrate for the enzyme being tested. The substrate is homogenized with the sample in the microchamber to form a test volume. The microchamber includes a working microelectrode that injects current to split water in the test volume to generate hydrogen ions and/or hydroxide ions and a micro-pH-electrode to measure a pH of the test volume; the slide also includes a reference microelectrode. The device includes a processor to adjust the injected current based on the pH of the test volume and determine an activity of the enzyme based on an amount the injected current is adjusted.

Abstract: One aspect of the present disclosure relates to an analyte sensor device. The analyte sensor device can include an optode layer that undergoes an optical change in the presence of an analyte. The analyte sensor device can also include a selectively-permeable membrane encapsulating the optode layer to form a stable membrane that that minimizes fouling of the analyte sensor device. The analyte sensor device can also include a plurality of microparticles that suppress a background physical interference on a detection of the optical change of the optode layer.

Abstract: One aspect of the present disclosure relates to a handheld device that can be used to perform a screening or diagnostic test. The handheld device can include a disposable microsampler unit, an analysis unit, a controller unit, and an output unit. The disposable microsampler unit can collect 10 microliters or less of a sample. The analysis unit can include two electrodes that can apply alternating periods of coulometry and potentiometry to the sample to determine a total content of a target chemical in the sample. During the coulometry period, the two electrodes are a working electrode and a counter electrode, and during the potentiometry period the two electrodes are an indicator electrode and a reference electrode. The controller unit can control the sequence of coulometry and potentiometry. The output unit can display the total content of the target chemical in the sample.

Abstract: The present disclose generally relates to optochemical imaging of a chemically active surface. A system that can facilitate such optochemical imaging can include an analyte-permeable membrane configured to prevent diffusion of outside contaminates into the system. The analyte permeable membrane comprising: a first surface; and a second surface opposed to the first surface configured to contact a chemically-active surface to permit diffusion of an analyte into the system from the chemically-active surface. The system also includes a measurement component coupled to the analyte-permeable membrane and configured to interact with the analyte. The interaction between the analyte and the measurement component causes a detectable change of a property of the measurement component.

Abstract: One aspect of the present disclosure relates to an analyte sensor device. The analyte sensor device can include an optode layer that undergoes an optical change in the presence of an analyte. The analyte sensor device can also include a selectively-permeable membrane encapsulating the optode layer to form a stable membrane that that minimizes fouling of the analyte sensor device. The analyte sensor device can also include a plurality of microparticles that suppress a background physical interference on a detection of the optical change of the optode layer.

Abstract: A system for multiparametric analysis includes a substrate and a three-dimensional (3D) cell aggregate. The substrate has a major surface and includes at least one radial electrode array. The 3D cell aggregate is disposed on the major surface of the substrate. The 3D cell aggregate has a longitudinal surface at least a portion of which covers one or more of the electrodes of the radial electrode array.

Abstract: A system for multiparametric analysis includes a substrate and a three-dimensional (3D) cell aggregate. The substrate has a major surface and includes at least one radial electrode array. The 3D cell aggregate is disposed on the major surface of the substrate. The 3D cell aggregate has a longitudinal surface at least a portion of which covers one or more of the electrodes of the radial electrode array.

Abstract: An in vitro sensor point-of-care sensor including a substrate, a sensing system, and a reference system. The substrate can include a first cavity and a second cavity. The sensing system can be disposed within the first cavity and include an optode membrane, a selectively-permeable membrane, and a plurality of microbeads. The optode membrane can be sensitive to an analyte in the biological fluid. The selectively-permeable membrane can cover an opening of the first cavity. The plurality of microbeads can be associated with at least one of the optode membrane and the selectively-permeable membrane. The reference system can be disposed within the second cavity.

Abstract: An in vitro sensor for point-of-care detection of at least one analyte or reaction product includes an inert, impermeable substrate, a sensing system, and a reference system. The substrate includes a first transparent surface oppositely disposed from a second surface and first and second cavities. Each of the first and second cavities defines an opening at the second surface. The sensing system is disposed in at least a portion of the first cavity and includes an analyte-detection optode membrane, an analyte-permeable membrane, and a plurality of non-transparent microbeads associated with at least one of the analyte-detection optode membrane and the analyte-permeable membrane. The analyte-permeable membrane is layered upon the analyte-detection optode membrane and covers the opening of the first cavity. The reference system is disposed in at least a portion of the second cavity.

Abstract: A system for multiparametric analysis includes a substrate and a three-dimensional (3D) cell aggregate. The substrate has a major surface and includes at least one radial electrode array. The 3D cell aggregate is disposed on the major surface of the substrate. The 3D cell aggregate has a longitudinal surface at least a portion of which covers one or more of the electrodes of the radial electrode array.

Abstract: An in vitro sensor for point-of-care detection of at least one analyte or reaction product includes an inert, impermeable substrate, a sensing system, and a reference system. The substrate includes a first transparent surface oppositely disposed from a second surface and first and second cavities. Each of the first and second cavities defines an opening at the second surface. The sensing system is disposed in at least a portion of the first cavity and includes an analyte-detection optode membrane, an analyte-permeable membrane, and a plurality of non-transparent microbeads associated with at least one of the analyte-detection optode membrane and the analyte-permeable membrane. The analyte-permeable membrane is layered upon the analyte-detection optode membrane and covers the opening of the first cavity. The reference system is disposed in at least a portion of the second cavity.

Abstract: A device for adjustment of the pH of a target liquid includes a working electrode (10), an electrolyte chamber (16) which holds an electrolyte (14), a counter electrode (12) in electrical contact with the electrolyte, a junction (18) which spaces the electrolyte from a target liquid (20) when the working electrode is in contact therewith, and a source of current (22), for supplying current to the working electrode for electrolysis of water at the working electrode, whereby the pH of the target solution is adjusted.

Abstract: A method of detecting an analyte in a fluid includes the step of positioning a sensor probe in the fluid. The sensor probe includes a sensing element which absorbs in the infrared region of the spectrum in response to the analyte. The change is then detected with a detection system.

Abstract: A sensor probe suited for implanting into the skin of a person includes a sensor body which may be formed from a polymer which includes 2-hydroxyethyl methacrylate (HEMA). A sensing system is supported by the body. The sensing system exhibits a detectable change when the probe is exposed to the analyte in the fluid. The sensing system may include an enzyme capable of catalyzing a reaction of the analyte to form a reaction product and a dye system which absorbs in the infrared region of the spectrum in response to the reaction product.

Abstract: A burette (10, 110, 200) suitable for delivery of a reagent into a target solution (50) employs diffusion for delivering the reagent. The reagent is in the form of a solution, which is combined with a matrix material (22), such as a gel or porous ceramic. A membrane (32) covers a delivery outlet (20) to the burette. In one embodiment, the delivery outlet comprises a plurality of fine bores (36), each one filled with or covered by a membrane (38). Stirring of the burette or target solution is achieved with a stirring means (104, 106). A heating or cooling means (80) heats a tip (16) of the burette.

Abstract: A device for adjustment of the pH of a target liquid includes a working electrode (10), an electrolyte chamber (16) which holds an electrolyte (14), a counter electrode (12) in electrical contact with the electrolyte, a junction (18) which spaces the electrolyte from a target liquid (20) when the working electrode is in contact therewith, and a source of current (22), for supplying current to the working electrode for electrolysis of water at the working electrode, whereby the pH of the target solution is adjusted.

Abstract: A sensor probe suited for implanting into the skin of a person includes a sensor body which may be formed from a polymer which includes 2-hydroxyethyl methacrylate (HEMA). A sensing system is supported by the body. The sensing system exhibits a detectable change when the probe is exposed to the analyte in the fluid. The sensing system may include an enzyme capable of catalyzing a reaction of the analyte to form a reaction product and a dye system which absorbs in the infrared region of the spectrum in response to the reaction product.

Abstract: A system for manipulation of a cell (100) includes a platform (33) which defines a surface (50) having a site (60) at which the cell has a higher probability of attachment in a period of time than on an adjacent area (52) of the surface. First and second syringes (10, 12) are selectively actuated to deliver a liquid to first and second tubes 26, 28, respectively. Outlets (29, 29?) of the first and second tubes are positioned so as to deliver the liquid to a liquid medium on the platform, thereby creating generally orthogonal fluid flows through the liquid to/from a region of interest (35). Cells located in the liquid medium at the region of interest move at a speed which is much lower than that of the liquid at the tube outlets and along the tube axis, allowing the cell to be manipulated to the site by manual or automated actuation of the syringes.

Abstract: A method for solving deconvolution problems where it is desired to reconstruct a signal over a time range or another variable of interest involves comparing shapes of measured and reconstructed plots. The optimization method is based on minimizing the error in shape (as opposed to the square errors in amplitude). A shape approach method characterizes similarity of two functions by computing the angle between the two when they are treated as two vectors in the n dimensional space where n is the number of data points it is desired to consider from both functions (the functions themselves may consist of more than n data points). A new approximation is then created by trying to decrease the disimilarity between the actual and predicted functions. This dissimilarity is measured as the angle between the two corresponding vectors, so the measure of dissimilarity is the size of the angle.