VHH Antibody Metal Microstructure Surface Plasmon Detection
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Solution Overview
Problem
Existing methods using fragmented antibodies struggle to detect low concentrations of analytes due to decreased antigen capturing ability, resulting in reduced detection sensitivity.
Innovation Solution
A detection device employing a metal microstructure with immobilized VHH antibodies and labeled VHH antibodies with fluorescent substances, utilizing surface plasmon resonance to enhance fluorescence detection, while maintaining antigen capturing ability and minimizing nonspecific adsorption through optimized surface roughness and self-assembled monolayers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fragmented antibodies are used as immobilized antibodies to shorten the distance between fluorescent substance and metal layer, then optical signal detection sensitivity is improved, but antigen capturing ability decreases
Solution Approach 1:
The antibody is segmented into a VHH domain (for immobilization on metal layer) and a fluorescent label (for detection). This segmentation allows the VHH to be positioned close to the metal layer for enhanced optical signal while the fluorescent label remains accessible for antigen binding and detection, resolving the contradiction between detection sensitivity and capturing ability
Solution Approach 2:
Different functional regions are assigned different properties: the VHH domain is positioned near the metal layer to maximize plasmonic enhancement of optical signals, while the C-terminus with fluorescent label is positioned away from the metal layer to maintain antigen binding capability. This local differentiation resolves the contradiction by optimizing each region for its specific function
2Measurement precision
If VHH antibodies are used to maintain antigen capturing ability, then detection sensitivity for low concentration analytes is improved, but nonspecific adsorption increases
Solution Approach 1:
A self-assembled monolayer (SAM) is introduced as an intermediary between the metal layer and the VHH antibody. The SAM provides a biocompatible interface that reduces nonspecific adsorption of analytes and other proteins to the metal surface, while still allowing specific antigen-VHH interactions. This intermediary layer resolves the contradiction by filtering out harmful nonspecific adsorption events
Solution Approach 2:
The surface chemistry parameters of the metal layer are changed by coating with a self-assembled monolayer, transforming the surface properties from metal-dominated (prone to nonspecific adsorption) to organic-molecule-dominated (biocompatible and selective). This parameter change resolves the contradiction by modifying surface characteristics to reduce harmful interactions
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
Enables the detection of low analyte concentrations with high sensitivity by improving fluorescence enhancement and reducing nonspecific adsorption, balancing capturing ability and fluorescence enhancement.
Implementation Method 1
surface plasmon being generated by irradiating the metal microstructure with excitation light
Implementation Method 2
fluorescence generated from the fluorescent substance by the irradiation of the excitation light
Data Source
AI summary
The present disclosure provides a detection device capable of detecting a low concentration of an analyte with high sensitivity. The detection apparatus according to the present disclosure comprises a metal microstructure on which a first VHH antibody having a property of binding specifically to the analyte is immobilized and which generate surface plasmon by being irradiated with excitation light, an inlet through which a second VHH antibody and a sample that may contain an analyte are introduced, wherein the second VHH antibody has a property of binding specifically to the analyte and is labeled with a fluorescent substance, a light source for irradiating the metal microstructure to which the second VHH antibody and the sample have been introduced with the excitation light, and a detection unit for detecting the analyte on the basis of fluorescence generated from the fluorescent substance by the irradiation of the excitation light.