Electro-Optic Grating-Coupled SPR Sensor Eliminates Moving Parts
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Solution Overview
Problem
Current surface plasmon resonance (SPR) technologies lack sensitivity to detect trace quantities of small molecules, especially in complex media, and are limited by the need for moving parts in angle-scanning instruments, making them fragile and unsuitable for field use.
Innovation Solution
An electro-optic grating-coupled surface plasmon resonance (EOSPR) platform is developed, featuring a sensor chip with an inert substrate, conductive layer, patterned electro-optic polymer, and thin gold layer, where the dielectric constant of the electro-optic polymer changes with applied voltage, allowing for sensitive detection of mass accumulation without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angle-scanning instruments are used for SPR detection, then measurement capability is achieved, but device complexity and fragility increase due to moving parts
Solution Approach 1:
The patent replaces the mechanical angle-scanning system with an electro-optic modulation system. Instead of physically moving components to change the angle of incidence, the invention uses voltage-controlled electro-optic polymers to modulate the effective refractive index, thereby controlling SPR resonance conditions electronically. This eliminates moving parts while maintaining SPR detection capability.
Solution Approach 2:
The invention changes the control parameter from mechanical angle to electrical voltage. By applying different voltages to the electro-optic polymer, the effective refractive index changes, which shifts the SPR resonance condition. This allows precise control of SPR detection without mechanical movement, resolving the contradiction between measurement capability and device complexity.
2Measurement precision
If conventional SPR techniques are used, then detection capability is provided, but sensitivity to trace quantities of small molecules is insufficient
Solution Approach 1:
The patent employs a composite structure consisting of electro-optic polymers combined with metal layers (such as gold) to form the sensor surface. This composite material system enhances the interaction between light and the analyte, improving the sensitivity of detection for trace quantities of small molecules. The electro-optic polymer provides both the structural matrix and the voltage-controlled refractive index modulation, while the metal layer supports surface plasmon resonance.
3Ease of operation
If portable field use is required, then accessibility is improved, but instrument fragility and complexity become prohibitive
Solution Approach 1:
By replacing mechanical angle-scanning components with solid-state electro-optic modulation, the invention eliminates fragile moving parts that would be problematic in portable field applications. The resulting device is more robust and better suited for handheld or field deployment while maintaining SPR detection functionality.
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 EOSPR platform enhances sensitivity, reduces instrument complexity and size, and increases portability, enabling high-content, hand-held assays with improved signal quality and reduced noise, suitable for field use and detecting faster reaction kinetics.
Implementation Method 1
An electro-optic grating-coupled surface plasmon resonance (EOSPR) platform is developed, featuring a sensor chip with an inert substrate, conductive layer, patterned electro-optic polymer, and thin gold layer, where the dielectric constant of the electro-optic polymer changes with applied voltage
Implementation Method 2
surface plasmon resonance (SPR) assays are based on the coupling of P-polarized incident light to a surface plasmon wave
Implementation Method 3
An electro-optic grating-coupled surface plasmon resonance (EOSPR) platform
Implementation Method 4
Surface plasmon resonance (SPR) assays are based on the coupling of P-polarized incident light to a surface plasmon wave, a physical mode created by charge density oscillations at a metal-dielectric interface
Data Source
AI summary
An instrument for measuring and analyzing surface plasmon resonance (SPR) and/or surface plasmon coupled emission on an electro-optic grating-coupled sensor surface is described herein. The sensor chip achieves SPR through a grating-coupled approach, with variations in the local dielectric constant at regions of interest (ROI) at the sensor surface detected as a function of the intensity of light reflecting from these ROI. Unlike other grating-based approaches, the metal surface is sufficiently thin that resonant conditions are sensitive to dielectric constant changes both above and below the metal surface (like the Kretschmann configuration). Dielectric constant shifts that occur as mass accumulates on the surface can be returned to reference intensities by applying voltage across the underlying electro-optic polymer. Approaches to the development of the sensor surfaces are described, as are software and hardware features facilitating sample handling, data gathering, and data analysis by this solid-state approach.