Graphene Plasmon Infrared Sensor for Protein Detection in Water
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing infrared spectroscopic techniques struggle with weak interaction between mid-infrared light and trace molecules in aqueous solutions due to strong water molecule absorption, requiring complex background signal subtractions and high sample amounts, and lack a suitable sensor combining micro-fluidic systems with graphene plasmon infrared detection.
Innovation Solution
A plasmon enhanced infrared sensor integrating a graphene plasmon infrared sensor with a micro-fluidic system, featuring a graphene layer with periodic nanostructures, a liquid top-gate, and an infrared transparent window, which enhances electromagnetic fields to localize molecules and eliminate water background signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional infrared spectroscopic techniques (ATR or transmission liquid cell) are used to analyze aqueous solutions, then quantitative analysis and structural identification can be performed, but complex background signal subtractions are required and high sample amount or concentration is demanded due to strong water molecule infrared absorption
Solution Approach 1:
The patent extracts and removes the harmful water background absorption signals through selective chemical etching of the silicon substrate, creating micropit structures that eliminate water signal interference while preserving the detection of analyte molecules
Solution Approach 2:
The patent creates localized regions with different properties: the silicon substrate is selectively etched in micropit areas to remove water signal, while the surrounding areas maintain their original structure for analyte detection, achieving spatially differentiated functionality
2Measurement precision
If conventional infrared spectroscopy is used to detect trace molecules in aqueous solutions, then molecular analysis can be performed, but the interaction between mid-infrared light and trace molecules is very weak due to the wavelength being 3 orders of magnitude greater than molecule size
Solution Approach 1:
The patent utilizes molecular vibration characteristics by exciting surface plasmon polaritons that resonate with the vibrational modes of target molecules, enhancing the interaction between infrared light and trace molecules through resonant coupling
Solution Approach 2:
The patent employs a composite structure combining silicon substrate with specific micropit geometries and metal coatings to create surface plasmon polariton resonators that enhance the electromagnetic field interaction with trace molecules
3Measurement precision
If graphene plasmon infrared sensor is used to enhance infrared response of molecules in solution, then local enhancement capacity and dynamic adjustability are achieved, but no suitable sensor is available for combining micro-fluidic system compatible with infrared transmission/reflection measurement due to strong infrared absorption of conventional micro-fluidic materials
Solution Approach 1:
The patent introduces an infrared-transparent window material as an intermediary component that allows infrared light to pass through the micro-fluidic system without being absorbed, enabling the integration of graphene plasmon sensor with micro-fluidic functionality
Solution Approach 2:
The patent designs a multi-functional device that combines infrared sensing, micro-fluidic sample handling, and surface plasmon polariton excitation in a single integrated platform, achieving universal applicability for trace molecule detection in liquid samples
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 sensor effectively enhances infrared absorption of molecules in aqueous solutions, allowing for direct and in-situ detection of protein fingerprints by modulating the Fermi level to eliminate water background signals and amplify molecular signals.
Implementation Method 1
Graphene plasmons can compress the wavelength of infrared light by more than 100 folds, and carriers in graphene hold the characteristic of massless Dirac fermions. Therefore, the plasmons have the advantages of high local enhancement capacity in an electric field
Implementation Method 2
the plasmons have the advantages of high local enhancement capacity in an electric field, dynamic adjustability, low intrinsic damping and the like, and can effectively enhance the infrared response of molecules
Implementation Method 3
the liquid top-gate is conditioned through a reference electrode; The sensor can dynamically modulate, repeatedly used and integrated
Data Source
AI summary
The invention provides a plasmon enhanced infrared spectrum sensor for detecting a protein secondary structure in an aqueous solution and a preparation method of the plasmon enhanced infrared spectrum sensor, and belongs to the technical field of infrared optical sensing. The sensor includes a graphene plasmon chip and a micro-fluidic system compatible with infrared transmission testing. Under excitation of incident infrared light, a locally enhanced electromagnetic field (surface plasmon) is formed on the surface of the graphene layer due to collective oscillation of charges, and molecules to be detected in an aqueous solution are enriched in a surface plasmon region due to Van der Waals interaction of the graphene layer. The infrared response of to-be-detected molecules gathered in the plasmon region is enhanced under the driving of an electromagnetic field of graphene plasmon; meanwhile, water molecules are excluded out of a plasmon region, molecular signals out of the plasmon region can be completely eliminated by using an in-situ electrical background deduction method, and direct and in-situ monitoring of trace solution components by infrared spectroscopy is realized.