Noninvasive Biosensor Using Inhibitor Monolayer for Glucose Detection
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Solution Overview
Problem
Conventional biosensors struggle with reducing the burden on the human body during sample collection and face decreased measurement sensitivity due to proteins like albumin in samples such as tears and saliva, which can interfere with glucose detection.
Innovation Solution
A biosensor design featuring an identification substance that binds to the target substance, an electrode charged with the identification substance, and an inhibitor with a longer molecular chain to prevent non-target substances from attaching, forming a self-assembled monolayer on the electrode surface to detect changes in charge density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a biosensor uses phenylboronic acid groups to bind to sialic acid samples for noninvasive detection, then the burden on the human body is reduced, but proteins in the sample act as noise and decrease measurement sensitivity
Solution Approach 1:
The patent segments the detection surface into distinct functional zones: phenylboronic acid groups for specific sialic acid binding, and oligoethylene glycol groups for non-specific protein repulsion. This segmentation allows the sensor to simultaneously achieve noninvasive operation and maintain measurement sensitivity by spatially separating the detection function from the anti-interference function.
Solution Approach 2:
The oligoethylene glycol groups act as an intermediary layer between the phenylboronic acid detection groups and the sample proteins. This intermediary layer specifically repels proteins through steric hindrance and hydrophilic interactions, preventing them from reaching the phenylboronic acid groups, while allowing the phenylboronic acid groups to freely access and bind sialic acid in the sample.
2Ease of operation
If proteins are present in samples like tears and saliva for noninvasive detection, then the sample can be collected easily, but the proteins interfere with glucose detection and reduce measurement accuracy
Solution Approach 1:
The patent applies local quality by giving different chemical properties to different parts of the detection surface. The phenylboronic acid regions have high affinity for sialic acid, while the oligoethylene glycol regions have high affinity for water and low affinity for proteins. This local differentiation allows the surface to simultaneously perform specific detection and general anti-fouling functions.
Solution Approach 2:
The patent converts the harmful effect of proteins (non-specific binding to detection surfaces) into a beneficial design feature by incorporating oligoethylene glycol groups that specifically repel proteins. The very presence of proteins in biological samples, which was previously a problem, becomes an opportunity to demonstrate the effectiveness of the anti-fouling oligoethylene glycol layer.
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
This design enhances measurement sensitivity by inhibiting non-target substances from binding, allowing for more reliable non-invasive glucose concentration measurement from samples like sweat, tears, and saliva.
Implementation Method 1
an identification substance that binds to a substance to be detected
Implementation Method 2
an inhibitor that inhibits a substance not to be detected from attaching to at least one of the identification substance and the electrode; the inhibitor is formed of a polymer compound having a longer molecular chain than the identification substance
Implementation Method 3
the inhibitor is formed of a polymer compound having a longer molecular chain than the identification substance
Implementation Method 4
a self-assembled monolayer is formed on a surface of the electrode from the identification substance and the inhibitor
Data Source
AI summary
A biosensor that can perform analysis based on a sample noninvasively collected from a human body is provided. The biosensor comprises an identification substance (38) that binds to a substance to be detected (40), and an electrode (16) charged with a charge of the identification substance (38), comprises an inhibitor (39) that inhibits a substance not to be detected (42) from attaching to at least one of the identification substance (38) and the electrode (16), and detects a change in a charge density of the electrode (16) caused by binding of the substance to be detected (40) to the identification substance (38).