Capillary Biosensor Electrode Arrangement for Double-Dosing Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing biosensors face challenges in accurately measuring analyte concentration in blood samples due to incomplete filling and double-dosing issues, which affect precision and introduce non-faradaic charging peaks.
Innovation Solution
A capillary-fill biosensor system with separate reference and counter electrodes, where the fluid sample completely covers the reference electrode before the counter electrode, and a test meter with circuitry to detect electrical circuits and trigger error conditions for insufficient sample, preventing double-dosing and ensuring accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a user applies a second drop of blood to top-up an incomplete sample, then the electrode coverage is improved, but the measurement precision deteriorates due to non-faradaic charging peaks
Solution Approach 1:
The system performs preliminary detection of electrical circuit completion between electrodes before initiating the measurement. This preliminary action identifies whether the sample has adequately covered the working electrode, preventing inaccurate measurements from incomplete samples while allowing users to know when proper coverage is achieved
Solution Approach 2:
The system provides feedback through error condition flags that indicate when double-dosing has occurred or when sample coverage is insufficient. This feedback mechanism guides users on proper sample application while maintaining measurement integrity by rejecting readings taken under suboptimal conditions
2Measurement precision
If fill-detection electrodes are added to detect complete filling, then the sample coverage detection is improved, but the device complexity increases
Solution Approach 1:
The patent makes the counter electrode serve dual functions: it acts as both the counter electrode for the electrochemical measurement and as a fill-detection electrode. By establishing an additional electrical circuit between the reference electrode and counter electrode, the system detects sample coverage without requiring separate detection electrodes, thereby maintaining measurement functionality while adding coverage detection capability
Solution Approach 2:
The system merges the fill-detection function with the existing counter electrode rather than adding separate detection electrodes. The electrical circuit between reference and counter electrodes serves both measurement and fill-detection purposes, reducing overall system complexity while achieving dual functionality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides stable and sensitive analyte concentration measurements, preventing double-dosing errors and ensuring accurate readings by ensuring complete sample coverage and timely detection of electrical circuits.
Implementation Method 1
a capillary-fill biosensor having a working electrode, a reference electrode and a counter electrode located within a capillary flow path
Implementation Method 2
circuitry for producing a first signal when an electrical circuit is detected between the reference electrode and the working electrode
Implementation Method 3
The electrodes respond electrochemically to the catalytic activity of the enzyme in the presence of a suitable analyte
Implementation Method 4
Electrochemical oxidation of hydrogen peroxide at platinum centres on the working electrode results in transfer of electrons from the peroxide to the electrode producing a current
Data Source
AI summary
A test system for measuring analyte concentration in a fluid sample includes:(i) a capillary-fill biosensor (20) having a working electrode (24), a reference electrode (22) and a separate counter electrode (23), arranged such that a fluid sample which flows evenly along the capillary flow path will substantially completely cover the reference electrode (22) before the fluid sample makes contact with any part of the counter electrode (23); and(ii) a test meter (42) for receiving the biosensor (20), the meter (42) including:first signal circuitry (31) for producing a first signal when an electrical circuit is detected between the reference electrode (22) and the working electrode (24);second signal circuitry (33) for producing a second signal when an electrical circuit is detected between the counter electrode (23) and at least one of the reference electrode (22) and the working electrode (24);a timer (35) for determining the time interval between production of said first signal and said second signal; anda processor (32) for triggering an error condition if said time interval exceeds a preset value or if said second signal is not produced within a preset time after said first signal is produced.