Creatinine Sensor Background Interference Mitigation
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Solution Overview
Problem
Existing biosensors face challenges in accurately measuring low concentrations of creatinine in biological fluids due to background interference from electroactive molecules like ascorbic acid.
Innovation Solution
A creatinine sensor is developed, comprising a first working electrode with a creatinine sensing layer containing a redox mediator, creatinine amidohydrolase, creatine amidinohydrolase, and sarcosine oxidase, and a first hydrophilic polyurethane membrane that is permeable to creatinine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a biosensor is designed to detect low concentrations of creatinine, then measurement sensitivity is improved, but background interference from electroactive molecules increases and reduces measurement accuracy
Solution Approach 1:
The sensing layer is segmented into multiple functional components: creatinine amidohydrolase for creatinine detection, ascorbate oxidase for ascorbic acid interference removal, and uric acid oxidase for uric acid interference removal. Each enzyme is positioned to perform its specific function, allowing simultaneous detection of creatinine and elimination of interfering substances
Solution Approach 2:
A redox mediator is introduced as an intermediary substance that facilitates electron transfer between the enzymes and the electrode. The mediator enables the enzymes to catalyze reactions and transfer electrons without direct contact between the electrode and interfering molecules, thereby improving sensitivity while reducing background interference
2Measurement precision
If the sensing layer includes multiple enzymes to reduce interference, then background signal interference is reduced, but device complexity increases
Solution Approach 1:
Multiple enzymes (creatinine amidohydrolase, ascorbate oxidase, and uric acid oxidase) are merged into a single integrated sensing layer that operates simultaneously. This consolidation allows the sensor to perform multiple functions (creatinine detection and interference removal) in one layer, reducing overall device complexity while maintaining signal accuracy
Solution Approach 2:
The sensing layer is designed with multi-functionality, where the same layer performs creatinine detection through creatinine amidohydrolase and simultaneously removes ascorbic acid and uric acid interference through their respective oxidases. This universal approach eliminates the need for separate sensing layers for each function
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 sensor achieves improved creatinine sensitivity and reduces background signal interference, enabling accurate and continuous creatinine monitoring in vivo.
Implementation Method 1
the redox mediator comprises a polymer and an electron transfer agent
Implementation Method 2
a first hydrophilic polyurethane membrane overcoating at least the creatinine sensing layer. In some aspects, the first hydrophilic polyurethane membrane is permeable to creatinine
Data Source
AI summary
The present disclosure relates to a creatinine sensor comprising a first working electrode, a creatinine sensing layer on the first working electrode comprising a redox mediator, creatinine amidohydrolase, creatine amidinohydrolase, and sarcosine oxidase, and a hydrophilic polyurethane membrane overcoating the creatinine sensing layer. The creatinine sensor can further comprise a background sensing electrode that does not detect creatinine. The present disclosure further relates to a method for sensing creatinine comprising exposing the creatinine sensor with a background sensing electrode to a fluid; applying a potential to the first and second working electrodes; obtaining a first signal from the first working electrode proportional to a concentration of creatinine and background interference in the fluid; obtaining a second signal from the second working electrode proportional to a concentration of background interference in the fluid; and determining the concentration of creatinine in the fluid by subtracting the second signal from the first signal.