Electrodes With Multilayer Membranes And Methods Of Making The Electrodes

Abstract

A sensor including a sensing layer is disposed over an electrode or an optode and a layer-by-layer assembled mass transport limiting membrane disposed over the sensing layer. The membrane includes at least one layer of a polyanionic or polycationic material. The assembled layers of the membrane are typically disposed in an alternating manner. The sensor also optionally includes a biocompatible membrane.

1 . (canceled) 
   
   
       2 . A system for monitoring analyte concentration in a biological sample of a host, the system comprising:
 a substantially continuous analyte sensor configured to produce a data signal indicative of an analyte concentration in a host during exposure of the sensor to a biological sample;   a reference solution, wherein the system is configured to expose the sensor to the reference solution, and wherein the system is configured to produce a data signal indicative of an analyte concentration in the reference solution during exposure of the sensor to the reference solution; and   a computer system comprising programming configured to determine calibration information and to calibrate a signal associated with a biological sample therefrom, wherein the calibration information comprises steady state information and transient information.   
   
   
       3 . The system of  claim 2 , wherein the reference solution has a known analyte concentration. 
   
   
       4 . The system of  claim 2 , wherein the calibration information is determined from a signal associated with exposure of the sensor to the reference solution and a signal associated with exposure of the sensor to the biological sample. 
   
   
       5 . The system of  claim 2 , wherein the steady state information comprises at least one of sensitivity information and baseline information. 
   
   
       6 . The system of  claim 5 , wherein the steady state information comprises sensitivity information and baseline information. 
   
   
       7 . The system of  claim 2 , wherein steady state information comprises information associated with a signal produced during exposure of the sensor to the reference solution. 
   
   
       8 . The system of  claim 7 , wherein the reference solution comprises a known analyte concentration of about zero, and wherein the steady state information comprises baseline information about the sensor in the reference solution. 
   
   
       9 . The system of  claim 7 , wherein the reference solution comprises a known analyte concentration of more than zero, and wherein the steady state information comprises sensitivity information about the sensor. 
   
   
       10 . The system of  claim 2 , wherein the steady state calibration information comprises reference data from an analyte sensor other than the substantially continuous analyte sensor. 
   
   
       11 . The system of  claim 2 , wherein transient information comprises a rate of change of a signal produced during exposure of the sensor to a step change in analyte concentration. 
   
   
       12 . The system of  claim 11 , wherein the rate of change comprises a rate change of a signal produced during exposure of the sensor to a biological sample of an unknown analyte concentration or an uncalibrated analyte concentration. 
   
   
       13 . The system of  claim 11 , wherein the rate of change comprises a rate change of a signal produced during exposure of the sensor to a biological sample, and wherein steady state information comprises reference data from an analyte sensor other than the substantially continuous analyte sensor. 
   
   
       14 . The system of  claim 2 , wherein transient information comprises response of a signal produced during exposure of the sensor to a change in analyte concentration. 
   
   
       15 . The system of  claim 14  wherein the response includes an impulse response, and the change in analyte concentration includes a step change in analyte concentration. 
   
   
       16 . The system of  claim 14 , wherein the response is used to determine an offset between a baseline measurement associated with the reference solution and a baseline measurement associated with a biological sample. 
   
   
       17 . The system of  claim 14 , wherein the response is used to determine a time point of a steady state measurement during which an analyte concentration can be obtained. 
   
   
       18 . The system of  claim 2 , wherein the transient information comprises a comparison of steady state information and transient information for a plurality of time spaced signals associated with biological samples of unknown analyte concentration or uncalibrated analyte concentration. 
   
   
       19 . The system of  claim 18 , wherein the comparison of steady state information and transient information is used to determine an offset between a baseline measurement associated with the reference solution and a baseline measurement associated with a biological sample. 
   
   
       20 . The system of  claim 18 , further comprising programming to detect a shift in baseline or sensitivity based on a comparison of steady state information and transient information. 
   
   
       21 . The system of  claim 20 , further comprising programming configured to initiate calibration of the signal to correct for a shift in at least one of baseline and sensitivity based on a comparison of steady state information and transient information. 
   
   
       22 . The system of  claim 20 , further comprising programming configured to calibrate of the signal to correct for a shift in at least one of baseline and sensitivity based on a comparison of steady state information and transient information. 
   
   
       23 . The system of  claim 2 , wherein the programming is configured to calibrate a signal is configured to perform at least one of initial calibration and update calibration. 
   
   
       24 . The system of  claim 2 , wherein the analyte sensor is a glucose sensor. 
   
   
       25 . A system for monitoring analyte concentration in a biological sample of a host, the system comprising:
 a substantially continuous analyte sensor configured to produce a data signal indicative of an analyte concentration in a host during exposure of the sensor to a biological sample;   a reference solution, wherein the system is configured to expose the sensor to the reference solution, and wherein the system is configured to produce a data signal indicative of an analyte concentration in the reference solution during exposure of the sensor to the reference solution; and   a computer system comprising programming configured to determine calibration information and to calibrate a signal associated with a biological sample therefrom, wherein the calibration information is determined from a signal associated with exposure of the sensor to the reference solution and a signal associated with exposure of the sensor a biological sample, wherein the biological sample is of unknown analyte concentration or uncalibrated analyte concentration.   
   
   
       26 . The system of  claim 25 , wherein the reference solution has a known analyte concentration. 
   
   
       27 . The system of  claim 25 , wherein calibration information comprises steady state information and transient information 
   
   
       28 . The system of  claim 25 , wherein steady state information comprises at least one of sensitivity information and baseline information 
   
   
       29 . The system of  claim 25 , wherein transient information comprises a rate of change of the sensor's signal responsive to exposure of the sensor to a change in analyte concentration 
   
   
       30 . The system of  claim 25 , wherein transient information comprises a rate of change of a signal produced during exposure of the sensor to a step change in analyte concentration. 
   
   
       31 . The system of  claim 25 , wherein the analyte sensor is a glucose sensor. 
   
   
       32 . A system for monitoring analyte concentration in a biological sample of a host, the system comprising:
 a substantially continuous analyte sensor configured to produce a data signal indicative of an analyte concentration in a host during exposure of the sensor to a biological sample;   a reference solution, wherein the system is configured to expose the sensor to the reference solution, and wherein the system is configured to produce a data signal indicative of an analyte concentration in the reference solution during exposure of the sensor to the reference solution; and   a computer system comprising programming configured to determine calibration information and calibrate a signal associated with a biological sample therefrom, wherein the calibration information is determined from at least one of a signal associated with exposure of the sensor to the reference solution and a signal associated with exposure of the sensor to a biological sample, wherein the biological sample is of unknown analyte concentration or uncalibrated analyte concentration.   
   
   
       33 . The system of  claim 32 , wherein the reference solution has a known analyte concentration. 
   
   
       34 . The system of  claim 32 , wherein the computer system further comprises programming configured to diagnose a condition of at least one of the sensor and the host responsive to calibration information. 
   
   
       35 . The system of  claim 32 , wherein calibration information comprises baseline information, and wherein the system comprises programming configured to determine an offset between a baseline associated with a reference solution and a baseline associated with a biological sample. 
   
   
       36 . The system of  claim 35 , wherein the offset is determined by processing an impulse response of the sensor's signal during exposure of the sensor to a step change in analyte concentration. 
   
   
       37 . The system of  claim 35 , wherein the offset is determined by a comparison of steady state information and transient information for a plurality of time spaced samples of a biological sample of unknown analyte concentration or uncalibrated analyte concentration. 
   
   
       38 . The system of  claim 35 , wherein the computer system further comprises programming configured to detect an interfering species. 
   
   
       39 . The system of  claim 38  wherein the interfering species is responsive to a change in the offset above a predetermined amount. 
   
   
       40 . The system of  claim 35 , wherein the computer system further comprises programming configured to diagnose a condition of the host's metabolic processes responsive to a change in the offset above a predetermined amount. 
   
   
       41 . The system of  claim 40 , wherein the computer system further comprises programming configured to display or transmit a message associated with the host's condition responsive to diagnosing the condition. 
   
   
       42 . The system of  claim 35 , wherein the computer system further comprises programming configured to diagnose an error and fail safe responsive to a change in the offset above a predetermined amount. 
   
   
       43 . The system of  claim 35 , wherein the computer system further comprises programming configured to recalibrate the sensor responsive to a change in the offset above a predetermined amount. 
   
   
       44 . The system of  claim 32 , wherein calibration information comprises sensitivity information, and wherein the system comprises programming configured to diagnose an error responsive to a change in sensitivity above a predetermined amount. 
   
   
       45 . The system of  claim 32 , wherein the computer system further comprises programming configured to calculate an response of a signal produced during exposure of the sensor to a change in analyte concentration, and wherein a time constant for the change is determined from the time of the peak response. 
   
   
       46 . The system of  claim 45  wherein the response of the signal includes an impulse response. 
   
   
       47 . The system of  claim 45  wherein the change in analyte concentration includes a step change. 
   
   
       48 . The system of  claim 45  wherein the time constant for the change includes a time constant for a step change. 
   
   
       49 . The system of  claim 45  wherein the time of the peak response includes the time of the peak impulse response. 
   
   
       50 . The system of  claim 45 , wherein the step of calculating an response is repeated more than one time, and wherein the computer system further comprises programming configured to diagnose a sensor condition or error responsive to a change in the time constants associated with the plurality of step changes above a predetermined threshold.