Abstract:
A method for formulating a glucose oxidase enzyme with peroxide resistant properties and a glucose oxidase enzyme formulated by the method. The enzyme formulation method results in a glucose oxidase enzyme with improve resistance to peroxide, and therefore, with improved resistance to oxidative inactivation. The method employs directed evolution techniques to evolve glucose oxidase to achieve the desirable properties. A peroxide resistant glucose oxidase may improve the longevity of, for example, glucose biosensors in which a peroxide resistant glucose oxidase may be placed.
Abstract:
A method and apparatus for enhancing the integrity of an implantable sensor. Voids formed between an outer tubing and a sensor substrate or spacing element may be back-filled with a curable, implantable material, minimizing the extent to which unwanted fluids diffuse within the sensor. An enzyme or protein matrix pellet below the sensor window may be pre-treated with a reducing agent to enhance its bond stability, and to reduce undesired swelling that may cause the sensor window to detach or leak. The bonding between the enzyme pellet and a hydrogel layer may be reinforced by application of an intervening bonding layer of a protein material, such as human serum albumin (HSA). The size of the window may be minimized by minimizing the size of an underlying electrode, providing reduced flux and lengthening sensor. A coating may be deposited on the surface of the sensor leads, providing stiffening and lubrication.
Abstract:
A substrate with hermetically sealed vias extending from one side of the substrate to another and a method for fabricating same. The vias may be filled with a conductive material such as, for example, a fritless ink. The conductive path formed by the conductive material aids in sealing one side of the substrate from another. One side of the substrate may include a sensing element and another side of the substrate may include sensing electronics.
Abstract:
A multilayer substrate device formed from a base substrate and alternating metalization layers and dielectric layers. Each layer is formed without firing. Vias may extend through one of the dielectric layers such that two metalization layers surrounding the dielectric layers make. contact with each other. The vias may be formed by placing pillars on top of a metalization layer, forming a dielectric layer on top of the metalization layer and surrounding the pillars, and removing the pillars. Dielectric layers may be followed by other dielectric layers and metalization layers may be followed by other metalization layers. Vias in the substrate may be filled by forming an assembly around the substrate, the assembly including printing sheets containing a conductive ink and pressure plates for applying pressure. A vacuum may be applied to remove air in the ink. Pressure may then be applied to the printing sheets through the pressure plates. The conductive ink in the printing sheets is pushed through the vias when pressure is applied by the pressure plates.
Abstract:
A sensing apparatus with a connector, a sensor lead and a sensor module with a spacer placed over electrodes that have been deposited on a substrate. The spacer may have a space for receiving an enzyme. End portions of the sensor module may be encapsulated, such as with molded beads. A sensor lead may attach to the sensor module and may have an outer tubing that passes over the module and attaches to the beads at the end of the sensor module. The sensor lead may also attach to the connector such that the sensing apparatus may be electrically coupled to a pump, electronics or other devices. The sensing apparatus may be implanted into a vein or artery.
Abstract:
A reusable analyte sensor site for use with a replaceable analyte sensor for determining a level of an analyte includes a site housing and a resealable insertion site coupled to one end of the site housing. Preferably, the site housing is formed to have an interior cavity, and includes an outer membrane made of a material selected to promote vascularization and having a first pore size, and an inner membrane made of a material selected to be free of tissue ingress. Also, the site housing permits the analyte to pass through the site housing to the interior cavity to permit measurement by the replaceable analyte sensor. The resealable insertion site is provided for inserting the replaceable analyte sensor into the interior cavity of the site housing.
Abstract:
A multilayer substrate device formed from a base substrate and alternating metalization layers and dielectric layers. Each layer is formed without firing. Vias may extend through one of the dielectric layers such that two metalization layers surrounding the dielectric layers make contact with each other. The vias may be formed by placing pillars on top of a metalization layer, forming a dielectric layer on top of the metalization layer and surrounding the pillars, and removing the pillars. Dielectric layers may be followed by other dielectric layers and metalization layers may be followed by other metalization layers. Vias in the substrate may be filled by forming an assembly around the substrate, the assembly including printing sheets containing a conductive ink and pressure plates for applying pressure. A vacuum may be applied to remove air in the ink. Pressure may then be applied to the printing sheets through the pressure plates. The conductive ink in the printing sheets is pushed through the vias when pressure is applied by the pressure plates.
Abstract:
A system and method for providing closed loop infusion formulation delivery which accurately calculates a delivery amount based on a sensed biological state by adjusting an algorithm's programmable control parameters. The algorithm calculates a delivery amount having proportional, derivative, and basal rate components. The control parameters may be adjusted in real time to compensate for changes in a sensed biological state that may result from daily events. Safety limits on the delivery amount may be included in the algorithm. The algorithm may be executed by a computing element within a process controller for controlling closed loop infusion formulation delivery. The biological state is sensed by a sensing device which provides a signal to the controller. The controller calculates an infusion formulation delivery amount based on the signal and sends commands to an infusion formulation delivery device which delivers an amount of infusion formulation determined by the commands.
Abstract:
A multilayer circuit substrate for multi-chip modules or hybrid circuits includes a dielectric base substrate, conductors formed on the base substrate and a vacuum deposited dielectric thin film formed over the conductors and the base substrate. The vacuum deposited dielectric thin film is patterned using sacrificial structures formed by shadow mask techniques. Substrates formed in this manner enable significant increases in interconnect density and significant reduction of over-all substrate thickness.
Abstract:
A reusable analyte sensor site for use with a replaceable analyte sensor for determining a level of an analyte includes a site housing material and a resealable insertion site coupled to one end of the site housing material. Preferably, the site housing material is formed to have an interior cavity with an opening. The site housing material is selected to promote tissue ingrowth and vascularization, and yet be free of tissue ingress. Also, the site housing material permits the analyte to pass through the site housing material to the interior cavity to permit measurement by the replaceable analyte sensor. The resealable insertion site provides a for inserting the replaceable analyte sensor into the interior cavity of the site housing material.