Aptamer-Based SERS Detection for Analyte Identification
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Solution Overview
Problem
Current point-of-care diagnostic tests face challenges such as inadequate sensitivity and specificity, leading to false negative and false positive results, particularly in complex biological samples like those for tuberculosis and anaesthetic monitoring, due to limitations in existing technologies like ELISAs and SERS assays that struggle with identifying and quantifying analytes in complex mixtures.
Innovation Solution
An aptamer-based Surface Enhanced Raman Scattering (SERS) detection technique that captures analytes onto a surface using specific aptamers, measures the SERS spectrum and signal intensity of the aptamer-analyte complex, and compares it to a database to verify the identity and quantify the analyte, thereby distinguishing true from false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ELISA is used for detecting analytes in biological samples, then the assay can detect certain analytes, but the sensitivity is inadequate leading to false negative results
Solution Approach 1:
The patent changes the detection parameter from traditional ELISA optical absorption to SERS signal enhancement, which provides significantly higher sensitivity. The SERS technique amplifies the Raman signal by factors of 10^6 to 10^8, enabling detection at much lower analyte concentrations and eliminating false negatives while maintaining reliability
Solution Approach 2:
The patent replaces the ELISA detection mechanism (enzyme-catalyzed color change) with a physical detection mechanism (Raman scattering enhanced by surface plasmons). This substitution eliminates the need for enzymatic reactions and provides direct, label-free detection with superior sensitivity and faster readout
2Measurement precision
If antibodies are used for detecting analytes, then the assay can identify target molecules, but the specificity is poor leading to false positive results due to cross-reactivity
Solution Approach 1:
The patent introduces aptamers as intermediary binding agents that replace antibodies. These synthetic nucleic acid molecules provide more specific binding to target analytes without the cross-reactivity issues that plague antibody-based assays, thereby improving specificity and reducing false positives
Solution Approach 2:
The patent changes the binding reagent from proteins (antibodies) to nucleic acids (aptamers), which offer superior specificity through programmable sequence-based recognition. This parameter change enables highly specific binding even in complex biological matrices, eliminating cross-reactivity with non-target molecules
3Measurement precision
If traditional detection methods are used in complex biological samples, then the assay can process samples, but the ability to distinguish true analytes from interfering substances is poor
Solution Approach 1:
The patent replaces complex separation and purification procedures with direct SERS detection. The technique's inherent ability to provide unique spectral fingerprints for each molecule allows direct identification and quantification of analytes in complex mixtures without preliminary sample preparation, simplifying the overall process while maintaining high accuracy
Solution Approach 2:
The patent uses the unique Raman spectral signature of each molecule as a molecular fingerprint or copy of its identity. By comparing the detected SERS spectrum against reference spectral libraries, the system can unequivocally identify the analyte of interest even in the presence of numerous interfering substances, providing unambiguous results in complex biological 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
This method provides direct and accurate identification and quantification of analytes in complex biological samples, improving sensitivity and specificity, and enabling real-time monitoring of anaesthetic concentrations, thus enhancing diagnostic accuracy and reducing false results.
Implementation Method 1
Surface Enhanced Raman Scattering is a well known vibrational spectroscopy technique that has attracted considerable attention for its ultra sensitive, extremely specific and low limit of detection of biomolecules
Implementation Method 2
The SERS phenomenon utilises the intense localised evanescent wave (an electromagnetic field) that can be produced at metal surfaces and junctions by optical excitation of the surface plasmons
Data Source
AI summary
An aptamer-based SERS detection technique that directly monitors an aptamer-analyte capture event by generating spectroscopic information regarding the identity of the analyte that has been bound to the aptamer from a complex biological sample. A reproducible SERS spectrum is measured for an aptamer-analyte complex formed on a metal surface and this spectral information is used directly to identify the specific aptamer-analyte complex and optionally also to quantify the analyte in the sample, thus enabling discrimination between true and false positives in quantitative analyte assays on complex biological samples. In one embodiment the aptamer is attached directly to the metal surface and surrounded by a self-assembled monolayer (SAM) of amphiphilic molecules. In an alternative embodiment the metal surface is coated with a SAM and the aptamer is attached to the amphiphilic molecules of the SAM.