A small diameter flexible electrode designed for subcutaneous in vivo amperometric monitoring of glucose is described. The electrode is designed to allow “one-point” in vivo calibration, i.e., to have zero output current at zero glucose concentration, even in the presence of other electroreactive species of serum or blood. The electrode is preferably three or four-layered, with the layers serially deposited within a recess upon the tip of a polyamide insulated gold wire. A first glucose concentration-to-current transducing layer is overcoated with an electrically insulating and glucose flux limiting layer (second layer) on which, optionally, an immobilized interference-eliminating horseradish peroxidase based film is deposited (third layer). An outer (fourth) layer is biocompatible.

Subcutaneous glucose electrode

A telemetered characteristic monitor system includes a remotely located data receiving device, a sensor for producing signal indicative of a characteristic of a user, and a transmitter device. The transmitter device includes a housing, a sensor connector, a processor, and a transmitter. The transmitter receives the signals from the sensor and wirelessly transmits the processed signals to the remotely located data receiving device. The processor coupled to the sensor processes the signals from the sensor for transmission to the remotely located data receiving device. The data receiving device may be a characteristic monitor, a data receiver that provides data to another device, an RF programmer for a medical device, a medication delivery device (such as an infusion pump), or the like.

Telemetered characteristic monitor system and method of using the same

An electrochemical analyte sensor formed using conductive traces on a substrate can be used for determining and/or monitoring a level of analyte in in vitro or in vivo analyte-containing fluids. For example, an implantable sensor may be used for the continuous or automatic monitoring of a level of an analyte, such as glucose, lactate, or oxygen, in a patient. The electrochemical analyte sensor includes a substrate and conductive material disposed on the substrate, the conductive material forming a working electrode. In some sensors, the conductive material is disposed in recessed channels formed in a surface of the sensor. An electron transfer agent and/or catalyst may be provided to facilitate the electrolysis of the analyte or of a second compound whose level depends on the level of the analyte. A potential is formed between the working electrode and a reference electrode or counter/reference electrode and the resulting current is a function of the concentration of the analyte in the body fluid.

Electrochemical analyte sensor

This invention is an implantable sensor and system capable of measuring, controlling, monitoring and reporting blood constituent levels. The implantable sensor (14) for sensing in vivo the level of at least one blood constituent in mammalian vascular tissue (20, 24) having at least one source of radiation from infrared through visible light, arranged to direct the radiation at the tissue where it is affected by interaction with the tissue, and at least one detector. The invention also encompasses a device for measuring and controlling the level of a blood constituent, such as glucose or oxygen, and includes an implantable infrared source and sensor module for generating an output signal representative of the sensed infrared radiation. The system includes a processor module responsive to the output signal which performs spectral analysis of the output signal and generates a control signal. The system further includes other devices for dispensing (16) doses of medications or controlling organ function in response to the control signal.

Implantable sensor and system for measurement and control of blood constituent levels

Methods and systems for providing data communication in medical systems are disclosed including a data communication unit to transmit one or more signals related to the monitored analyte level received from the analyte sensor to a remote device.

Analyte monitoring system and methods

To explore the clinical performances of the needle-type glucose sensor, in vivo monitoring was conducted in human subjects. The tissue glucose concentrations measured by glucose sensor were lower than the plasma glucose concentrations by 15%, but a good linear relationship was observed between the tissue and plasma glucose concentrations. The sensing sites between abdomen and forearm did not affect the tissue glucose monitoring. The tissue glucose concentrations after meal intake showed 5 min delayed response to the blood glucose concentrations. After 3 days' continuous monitoring, the "relative" sensor output to the plasma glucose concentration decreased by 26% and the "relative" response time to reach peak value prolonged from 5 min to 13.5 min. These data indicate the clinical usefulness of the needle-type glucose sensor.

Nao K

Papers

In vivo characteristics of needle-type glucose sensor--measurements of subcutaneous glucose concentrations in human volunteers.