Single-Protein Electrode Sensing Below the Noise Threshold
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Solution Overview
Problem
Existing methods for electrical measurement of enzyme activity are hindered by voltage-induced fluctuations, making it difficult to distinguish functional motions from non-functional noise, and require direct electrical connection to the enzyme for accurate measurement.
Innovation Solution
A device comprising closely spaced electrodes with a protein attached, allowing for direct electrical measurement by applying a bias below the voltage threshold that induces noise, enabling detection of functional protein fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high bias voltage is applied to the electrodes to enable direct electrical measurement, then the signal strength from protein activity increases, but voltage-induced fluctuations and noise increase making it difficult to distinguish functional motions
Solution Approach 1:
The patent applies parameter changes by carefully controlling the bias voltage to remain below the threshold that induces noise fluctuations. This allows the system to operate in a regime where direct electrical measurement is possible without triggering the harmful voltage-induced fluctuations, thus resolving the contradiction between signal strength and noise generation
Solution Approach 2:
The patent uses an intermediary approach by introducing a redox mediator that facilitates electron transfer between the protein and electrode. This mediator enables electrical measurement at lower bias voltages, avoiding the direct high-voltage-induced fluctuations while still achieving sufficient signal strength for detection
2Object-affected harmful factors
If indirect field effect transistor measurement is used to detect enzyme activity, then voltage-induced noise is avoided, but direct electrical connection to the enzyme is lost reducing measurement accuracy
Solution Approach 1:
The patent employs a redox mediator as an intermediary substance that bridges the gap between the protein and electrode. This mediator enables direct electrical connection and accurate measurement while allowing operation at low bias voltages that avoid voltage-induced noise, thus resolving the contradiction between noise avoidance and measurement accuracy
Solution Approach 2:
The patent replaces the indirect mechanical coupling of FET measurement with direct electrical measurement through electron transfer mediated by redox couples. This substitution enables more accurate direct measurement of protein activity while maintaining noise-free operation through appropriate bias voltage control
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
Enables direct electrical measurement of protein activity without voltage-induced noise, allowing for accurate detection of functional protein motions and sequencing of biopolymers with high precision and speed.
Implementation Method 1
applying a bias between the first and second electrode of value such that spontaneous fluctuations of the current between the electrodes do not occur
Implementation Method 2
observing fluctuations in current between the two electrodes that arise when the chemical entity interacts with the protein
Data Source
AI summary
The present disclosure relates to a device, system and method for sensing functional motions of a single protein molecule via direct attachment of one or more electrodes to the molecule. The present disclosure also relates to an array, a system comprising an array and method for sequencing a biopolymer using an array.