Dielectric Film SPR Sensor for Small Molecule Kinetics
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Solution Overview
Problem
Conventional SPR sensors face challenges in accurately measuring the binding and dissociation kinetics of small molecular bio materials due to sensitivity limitations and interference from changes in the reflective index of the buffer solution, and they require expensive noble metal thin films with unstable optical characteristics.
Innovation Solution
An apparatus and method utilizing a micro flow path structure with a thin dielectric film, polarized incident light, and ellipsometry/reflectometry to quantify binding and dissociation kinetics without influence from buffer solution index changes, featuring a semiconductor or dielectric substrate, self-assembled monolayers, and optimized light polarization for high-sensitivity measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional SPR sensor uses a thin metal film to measure binding kinetics, then the measurement can be performed in real-time without labeling, but the measurement sensitivity is insufficient for small molecular bio materials and the results are influenced by buffer solution refractive index changes
Solution Approach 1:
The patent changes the fundamental optical parameters of the sensor structure by replacing the metal film with a dielectric film having different refractive index properties. This parameter change enables the system to achieve both high measurement sensitivity (detecting thickness changes of 0.01 nm or lower) and reliability by eliminating the harmful influence of buffer solution refractive index changes on the measurement results.
2Reliability
If a conventional SPR sensor uses a thin metal film, then surface plasmon resonance can be achieved, but the optical characteristics are unstable and manufacturing costs are high due to expensive noble metals
Solution Approach 1:
The patent replaces expensive noble metal thin films (gold, silver) with inexpensive dielectric film materials such as silicon oxide, silicon nitride, or silicon oxynitride. This substitution dramatically reduces manufacturing costs while providing stable optical characteristics and reliable performance for binding kinetics measurement.
Solution Approach 2:
The patent employs composite material structures combining dielectric films with semiconductor substrates. This composite approach provides both mechanical support and stable optical properties, achieving reliable optical characteristics without the cost and instability issues of noble metal films.
3Measurement precision
If an ellipsometer is used for thickness measurement of oxide films, then high measurement sensitivity is achieved, but the technique requires high contrast in refractive index which limits its application to specific materials
Solution Approach 1:
The patent creates a universal sensor platform using dielectric films that can measure binding kinetics for diverse bio materials including proteins, DNA, viruses, and small molecules. The dielectric film structure provides consistent high measurement sensitivity (0.01 nm or lower) across different material types, eliminating the refractive index contrast limitations of conventional ellipsometry while maintaining broad material applicability.
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 allows for accurate, high-sensitivity measurement of binding and dissociation kinetics of small molecular bio materials with reduced manufacturing costs and improved reliability, independent of buffer solution index changes, enabling efficient analysis in a liquid immersion micro flow path environment.
Implementation Method 1
a polarization generation unit (300) for radiating incident light, polarized through the incident window (142), to the binding layer (160) at an angle of incidence θ satisfying a p-wave non-reflecting condition
Implementation Method 2
The present invention relates to an apparatus and method for quantifying the binding and dissociation kinetics of molecular interactions of small molecular bio materials by using an ellipsometry and a reflectometry
Implementation Method 3
a polarization detection unit (400) for detecting a change in the polarization of reflected light of the binding layer (160) which is incident through the reflection window (144)
Data Source
AI summary
The present invention relates to an apparatus for quantifying the binding and dissociation kinetics of molecular interactions of small molecular bio materials with high sensitivity almost without the influence of a change in the reflective index resulting from a buffer solution by making polarized incident light incident on the binding layer of a bio material, formed in a thin dielectric film, so that the polarized incident light satisfies a p-wave non-reflecting condition and a quantifying method using the same.