Aptamer Fiber-Optic Waveguide Sensor for Ultrasensitive Detection
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Solution Overview
Problem
Current methods for detecting small molecule contaminants, such as those in food and environmental samples, face challenges due to high equipment costs, complex sample preparation, and limited sensitivity, especially in complex mediums, which are not suitable for field testing and often require expensive instruments.
Innovation Solution
Combining Solid-Phase Microextraction (SPME) with aptamers on a fiber-optic waveguide sensor (SPME-OWS) for simultaneous target enrichment, purification, and detection, enabling ultrasensitive and highly specific detection of small molecules without the need for extensive sample pretreatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fiber-optic waveguide sensors are used for detecting small molecule contaminants, then the detection can be performed with simple operation, but the detection limit is mostly at the nM level which cannot achieve the limit standard of small molecules contaminants in complex medium
Solution Approach 1:
The patent combines Solid-Phase Microextraction (SPME) with fiber-optic waveguide sensing to create an integrated sensor system. The SPME fiber coating is directly formed on the optical fiber surface, merging the enrichment function with the detection function in a single device, thereby achieving ultra-sensitive detection without requiring separate sample preparation equipment
Solution Approach 2:
The SPME fiber coating performs preliminary enrichment and concentration of target molecules from complex media before the detection process. This preliminary action concentrates the analyte at the sensing interface, enabling detection at concentrations well below the original sample concentration and achieving the required detection limits
2Measurement precision
If Large-scale Instruments such as Vapour phase chromatography and HPLC are used for detecting small molecule contaminants, then high measurement precision can be achieved, but expensive equipment, high work environment, and equipment maintenance are required which are not suitable for field testing
Solution Approach 1:
The patent extracts the essential detection function from complex laboratory instruments like HPLC and GC, isolating the core capability of small molecule detection into a portable fiber-optic sensor. By removing the need for complex chromatographic separation systems and retaining only the essential sensing and enrichment functions, the device becomes suitable for field testing while maintaining detection precision
Solution Approach 2:
The patent replaces complex mechanical chromatographic separation systems with a biochemical approach using aptamers for target recognition and SPME for enrichment. This substitution eliminates the need for complex mechanical instruments while achieving comparable or superior detection capability in a portable format
3Reliability
If aptamers are used for detecting small molecules, then high specificity can be achieved without requiring expensive equipment, but the affinity of aptamers for small molecules is generally much lower than antibody and detection sensitivity cannot achieve the actual required level
Solution Approach 1:
The patent introduces SPME fiber coating as an intermediary enrichment layer between the sample matrix and the aptamer sensing interface. This intermediary structure concentrates target molecules from dilute solutions, effectively bridging the gap between the low affinity of aptamers and the requirement for high detection sensitivity by pre-concentrating the analyte before it interacts with the aptamer
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
Achieves detection limits 625-2000 times lower than conventional fiber-optic waveguide sensors and 325-20,000 times lower than electrochemical methods, with high specificity and anti-matrix interference ability, allowing for direct detection in complex samples like milk, lake water, and wine with reduced sample dilution requirements.
Implementation Method 1
total reflection of light is generated when laser enters into the light sparing substance from the light dense substance at a certain angle of incidence, a portion of laser will transmit in vertical direction of optical fiber
Implementation Method 2
the strength of this portion of laser will decrease exponentially with distance left from the optical fiber, which is called the evanescent wave. The evanescent wave can excite fluorescent group within the range of the evanescent wave transmission
Implementation Method 3
The evanescent wave can excite fluorescent group within the range of the evanescent wave transmission
Implementation Method 4
Aptamers can specifically recognize the varied target molecule ranging from proteins, small molecules, cells, to tissue
Implementation Method 5
Solid-phase microextraction (SPME) is one new type of extraction technology in rapid development in recent years, which uses various enrichment materials attached to solid-phase to enrich and purify all kinds of targets
Data Source
AI summary
The invention relates to a fiber-optic wave guide sensor of aptamers having functions of in situ target enrichment and purification, and a method for detection of small molecules to realize the quantitative detection of small molecules targets based on that small molecules targets and the aptamers complementary short strand DNA competitively bind with aptamers tethered on the fiber surface. It synchronously realized specifically binding aptamers with targets and in situ target enrichment and purification of targets by modifying aptamers and solid micro extraction layer with silica fibers of the fiber-optic wave guide sensor, which can achieve the ultrasensitive and ultrahigh specific quick detection for all types of small molecule targets regardless of any signal amplification reaction based on enzyme. The detection limitation is very low with good generalizability.