SERS Substrate with Anisotropic Nanostructures for Trace Analyte Detection
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Solution Overview
Problem
Conventional Raman spectroscopy has limited sensitivity for characterizing biological samples with target analytes present in small quantities, and even with surface-enhanced Raman scattering (SERS) effects, there is a need for more sensitive SERS-active reporter molecules to enhance the Raman signal.
Innovation Solution
A substrate comprising a micro- or nanostructured periodic array of anisotropic metallic micro- or nanostructures with Raman-active linker molecules directly bound to them, and capture molecules bound to the linker molecules, which induces a uniform plasmonic field and enhances the Raman signal without the need for bound/free separation or washing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Raman spectroscopy is used to detect analytes in biological samples, then the measurement process is simple, but the sensitivity is insufficient for detecting small quantities of target analytes
Solution Approach 1:
The patent changes the physical state and optical properties of the metal surfaces by creating periodic nanostructures with specific geometries (spheres, rods, plates, etc.) arranged in regular patterns. This structural parameter change generates localized surface plasmon resonances that dramatically enhance the Raman scattering cross-section of adsorbed molecules, enabling detection of trace analytes while maintaining a relatively simple measurement process
Solution Approach 2:
The patent combines metal nanostructures (gold, silver, aluminum, copper, or their alloys) with dielectric substrates to create composite SERS substrates. This composite structure leverages the plasmonic properties of metals and the mechanical stability of dielectrics, achieving both high detection sensitivity and operational simplicity
2Measurement precision
If SERS-active reporter molecules are used to enhance the Raman signal, then the detection sensitivity improves, but the cost and complexity of the assay increases
Solution Approach 1:
The patent employs analyte-specific capture molecules (antibodies, aptamers, or other recognition elements) that are directly immobilized on the SERS-active metal nanostructures. These capture molecules selectively bind target analytes from complex biological samples without requiring additional labeling steps, bound/free separation, or washing processes. The SERS signal enhancement occurs automatically upon analyte binding, enabling direct detection with high sensitivity and simplified assay procedures
Solution Approach 2:
The patent extracts and eliminates the complex bound/free separation and washing steps that are traditionally required in immunoassays. By using SERS-active substrates with immobilized capture molecules, the assay directly measures bound analyte complexes on the substrate surface, removing unnecessary procedural steps and reducing both time and operational complexity
3Productivity
If conventional immunoassay methods are used for determining analyte concentrations, then the measurement process is established, but the analysis time and operational complexity increase due to required separation and washing processes
Solution Approach 1:
The patent removes the bound/free separation and washing steps from the conventional immunoassay workflow by using SERS detection of analyte-capture molecule complexes directly on the substrate surface. This extraction of unnecessary steps dramatically reduces analysis time and operational complexity while maintaining the ability to accurately determine analyte concentrations in biological samples
Solution Approach 2:
The patent enables continuous detection by eliminating the interruption caused by separation and washing steps. The SERS measurement can be performed continuously on the substrate with immobilized capture molecules, allowing for rapid, uninterrupted analysis of analyte concentrations and improving overall productivity
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 provides a highly sensitive and cost-effective platform for determining analyte concentrations, significantly improving upon conventional immunoassay methods by eliminating the need for costly separation processes and reducing analysis time, while maintaining high sensitivity.
Implementation Method 1
When a Raman-active molecule is adsorbed on or in close proximity to, e.g., within about 5 nm, a metal surface, the intensity of a Raman signal arising from the Raman-active molecule can be enhanced. This enhancement is referred to as the surface-enhanced Raman scattering (SERS) effect.
Implementation Method 2
The mechanism by which SERS occurs is thought to result from a combination of (i) surface plasmon resonances in the metal that enhance the local intensity of the incident light
Implementation Method 3
each of the plurality of nanostructures induce an average maximum and substantially uniform plasmonic field greater than 10^8 across the substrate
Data Source
AI summary
The disclosure relates to a substrate comprising a micro- or nanostructured periodic array comprised of a plurality of anisotropic metallic micro- or nanostructures, wherein each of the plurality of nanostructures induce an average maximum and substantially uniform plasmonic field greater than 108 across the substrate; a plurality of Raman-active linker molecules directly bound to the metallic micro- or nanostructures; and a plurality of capture molecules directly bound to the Raman-active linker molecules. The disclosure also relates to systems, devices, and methods that use the substrates to determine the concentration of various analytes.