LSPR Aptamer Sensor Sensitivity via Intercalating Agent
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Solution Overview
Problem
Current aptamer sensors face limitations in sensitivity due to the small electromagnetic field generated by nano-sized metal particles, particularly when detecting small molecular weight biomolecules, which restricts the detection range and sensitivity.
Innovation Solution
An aptamer sensor is developed with metal nanoparticles, where an aptamer forms a complex structure with a target material and an intercalating agent like berberine is introduced to increase the local refractive index and molecular density, enhancing the absorption spectrum shift through LSPR, thereby improving sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If metal nanoparticles are used for LSPR-based sensing, then the sensor can detect biomolecules with ease and perform simultaneous analysis of multiple samples, but the sensitivity is reduced due to the small electromagnetic field generated by nanometer-sized metal particles
Solution Approach 1:
An intercalating agent is introduced as an intermediary substance between the aptamer and the target material. This agent accumulates at the binding interface and amplifies the LSPR signal by enhancing the local refractive index change, thereby mediating between the nanoparticle's limited electromagnetic field and the need for high sensitivity detection
Solution Approach 2:
The patent changes the physical-chemical parameters of the sensing interface by introducing an intercalating agent that alters the local refractive index and molecular density. This parameter change amplifies the optical signal without requiring larger metal particles, thus maintaining the nanoscale advantages while improving sensitivity
2Measurement precision
If the electromagnetic field size is increased to improve sensitivity, then the detection capability is enhanced, but the range in which material can be sensed is reduced
Solution Approach 1:
The intercalating agent creates a localized zone of enhanced refractive index and molecular density precisely at the aptamer-target binding interface. This local quality enhancement concentrates the sensing effect in a specific region, maximizing sensitivity without expanding the overall sensing area beyond the nanoparticle vicinity
3Device complexity
If aptamer directly binds to target material on metal nanoparticle surface, then the sensor structure is simple, but the absorption spectrum shift is insufficient for detecting small molecular weight biomolecules
Solution Approach 1:
The intercalating agent serves as a mediator that inserts itself between the aptamer and target material, adding a functional layer that amplifies the optical signal. While this adds structural complexity, it significantly enhances the absorption spectrum shift by increasing molecular density and refractive index at the sensing interface
Solution Approach 2:
The sensor structure becomes a composite system comprising metal nanoparticles, aptamers, intercalating agents, and target materials. This composite structure leverages the plasmonic properties of metal nanoparticles combined with the molecular recognition capability of aptamers and the signal amplification of intercalating agents, achieving enhanced detection capability
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 sensitivity and detection range of the aptamer sensor are significantly enhanced, with the detection range expanded from 1 nM to 1 μM to 1 pM to 10 μM, and sensitivity increased by about 1000 times when using berberine as the intercalating agent.
Implementation Method 1
When light having various wavelengths is emitted onto a material existing on a local surface such as metal nanoparticles, polarization occurs on the surface of metal nanoparticles and exhibits a unique characteristic of increasing the intensity of the electric field. Electrons formed by polarization form a group (plasmon) and locally vibrate on the surface of the metal nanoparticles. This phenomenon is called localized surface plasmon resonance (LSPR).
Implementation Method 2
an intercalating agent inserted between the aptamer and the target material in reaction of the aptamer with the target material to increase shift of an absorption spectrum due to increase of local refractive index and molecular density through aggregation toward the metal nanoparticles surface
Data Source
AI summary
Disclosed herein is an aptamer sensor including a substrate having metal nanoparticles formed thereon, an aptamer attached to surfaces of the metal nanoparticles to form a structure by selectively reacting with a target material to be detected, and an intercalating agent inserted between the aptamer and the target material in reaction of the aptamer with the target material to increase shift of an absorption spectrum due to local surface plasmon resonance sensor through aggregation toward the metal nanoparticles.