Biosensor Chip Using High Extinction Coefficient Marker
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Solution Overview
Problem
Current biosensor technologies face limitations in measuring ultralow-concentration biological substances due to insufficient sensitivity, particularly in detecting changes in refractive index and surface thickness, which affects the reliability and accuracy of biological substance analysis.
Innovation Solution
The use of a marker with a large extinction coefficient and a dielectric substrate amplifies the elliptical polarization signal by causing a significant change in refractive index, allowing for enhanced sensitivity and accuracy in measuring biological reactions, such as antigen-antibody interactions, and improving signal amplification by minimizing steric hindrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional ellipsometer is used to measure thin film thickness, then nanometer-level measurement is achieved, but measurement sensitivity is insufficient for biological substances with thickness below 0.01 nm
Solution Approach 1:
The patent changes the measurement parameter from conventional thickness measurement to Brewster's angle measurement. By measuring the shift in Brewster's angle (ΔθB) instead of direct thickness, the system achieves high sensitivity for ultrathin films below 0.01 nm because the Brewster's angle is extremely sensitive to refractive index changes at the interface, allowing reliable detection of monolayer and sub-monolayer biological substances.
Solution Approach 2:
The patent transitions from measuring one dimension (thickness) to measuring another dimension (angle). By measuring the angular position of Brewster's angle rather than direct thickness, the system achieves enhanced sensitivity for ultralow-concentration biological substances, effectively measuring in a different parameter space where the signal is amplified.
2Measurement precision
If a large-sized marker is used to amplify the elliptical polarization signal, then measurement sensitivity is improved, but steric hindrance occurs that hinders biological substance bonding reactivity
Solution Approach 1:
The patent changes the amplification mechanism from size-based amplification to refractive index-based amplification. Instead of using large markers that physically amplify the signal but cause steric hindrance, the system uses markers with high refractive index (n > 1.5) that amplify the Brewster's angle shift signal through optical property changes, eliminating steric hindrance while maintaining signal amplification.
Solution Approach 2:
The patent replaces the mechanical amplification approach (using large physical markers) with an optical amplification approach (using high refractive index markers). The signal amplification is achieved through optical property differences rather than physical size differences, substituting a mechanical system with an optical field-based system that avoids steric hindrance.
3Measurement precision
If metal particles are used as markers for signal amplification, then the measurement signal is increased, but the effect is limited to within 200 nm from the surface and requires expensive additional devices
Solution Approach 1:
The patent extracts the essential function of signal amplification from complex LSPR systems with metal particles and isolates it to a simple high refractive index marker. By removing the metal particle component and its associated 200 nm distance limitation and complex analysis requirements, the system retains only the refractive index-based signal amplification mechanism that works with conventional ellipsometers.
Solution Approach 2:
The patent replaces expensive metal particle markers with simple, inexpensive high refractive index markers (n > 1.5). These markers provide sufficient signal amplification without requiring expensive additional devices or complex analysis algorithms, making the system more accessible and easier to operate while achieving comparable or superior performance.
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 approach significantly enhances the sensitivity and accuracy of biosensor measurements, achieving signal amplification of up to dozens of times compared to traditional methods, enabling the detection of ultralow molecular weight substances and improving analytical performance in various fields, including medical and environmental applications.
Implementation Method 1
amplifies an elliptical polarization signal
Implementation Method 2
causing a significant change in refractive index
Implementation Method 3
marker having a large extinction coefficient
Implementation Method 4
incident light is incident at a specific incident angle and is reflected from the dielectric substrate
Data Source
AI summary
The present chip relates to a high-sensitive biosensor chip using a high extinction coefficient marker and a dielectric substrate, a measurement system, and a measurement method and, more specifically, to an ellipsometry-based high-sensitive biosensor technology or a measurement method using same, the technology amplifying an elliptically polarized signal by a marker having a high extinction coefficient and a dielectric substrate. The marker and the substrate used in the present chip measure a Brewster's angle shift or an elliptical polarization measurement angle with respect to an ultra-low concentration biological material (e.g. antibody or DNA).