Metallic Particle Plasmon Resonance in FTIR Fluid Detection
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Solution Overview
Problem
Existing optical detection systems for particles in fluids, such as blood or serum, lack sensitivity and are not well-suited for portable, point-of-care applications, as they require cumbersome equipment and have limited ability to detect low concentrations of particles effectively.
Innovation Solution
The use of metallic particles that induce localized plasmon resonance in an FTIR system, allowing for enhanced sensitivity through increased interaction with the evanescent field and detection of localized plasmon resonance in the reflected wave, combined with a handheld device design featuring low-cost, low-magnification optics and multispectral imaging for improved signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical detection systems are used, then the system structure is simple, but the sensitivity of particle detection is low
Solution Approach 1:
The patent changes the optical parameters by introducing metallic particles with localized surface plasmon resonance properties. These particles exhibit resonant scattering at specific wavelengths, which significantly enhances the optical signal when they bind to the sensor surface, thereby improving detection sensitivity without requiring complex system modifications
Solution Approach 2:
The patent employs composite structures consisting of metallic particles (gold, silver, or aluminum) combined with functional layers (such as antibodies or other binding molecules) on the sensor surface. This composite approach enables both high sensitivity through plasmon resonance and specific particle detection through functional binding, resolving the contradiction between sensitivity and complexity
2Measurement precision
If high-sensitivity detection systems are implemented, then particle detection capability is improved, but the device becomes cumbersome and unsuitable for portable use
Solution Approach 1:
The metallic particles themselves serve as the signal amplification mechanism through their intrinsic localized surface plasmon resonance properties. This self-service approach eliminates the need for external signal amplification devices or complex detection optics, enabling high sensitivity in a compact, portable format
Solution Approach 2:
The patent employs disposable sensor cartridges or test strips containing pre-functionalized metallic particles. This approach allows high-sensitivity detection in portable devices while keeping each unit simple and replaceable, suitable for point-of-care testing applications
3Measurement precision
If conventional detection methods are used, then the equipment is simple, but the ability to detect low concentrations of particles is limited
Solution Approach 1:
The metallic particles exhibit resonant oscillation of conduction electrons (localized surface plasmon resonance) when illuminated by light at specific wavelengths. This resonant effect dramatically enhances the scattering cross-section of individual particles, enabling detection of low concentrations without requiring complex equipment
Solution Approach 2:
The localized surface plasmon resonance of metallic particles causes wavelength-specific scattering that appears as characteristic color changes or spectral features. This optical signature provides a sensitive and specific signal that can be detected with simple optics, enabling low concentration detection without complex instrumentation
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 significantly enhances the sensitivity of particle detection, enabling the identification of lower particle concentrations and allowing for more reliable and portable optical detection systems, suitable for clinical diagnostics and other applications.
Implementation Method 1
The use of metallic particles that induce localized plasmon resonance in an FTIR system, allowing for enhanced sensitivity through increased interaction with the evanescent field
Implementation Method 2
FTIR comprises illuminating a sensor surface with an incident beam at an angle such that it is totally reflected thereon. An evanescent light field of several tens to few hundreds nanometers is formed accordingly on the sensor surface.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a system for optically detecting particles (400) in a fluid (200). It comprises on the one hand a sensor platform (300) with a sensor surface (350) to receive said particles (400) and a material extending from the sensor surface (350) having a refractive index higher than the one of the fluid (200), such that an electromagnetic wave (10) propagating in this platform material (310) and incident to the sensor surface (350) at an angle greater than the critical optical angle is totally reflected onto the sensor surface (350). Said particles (400) comprise a metallic material (410) enabling a localized surface plasmon resonance at at least one resonant wavelength(s) if excited at excitation wavelength(s). They are further arranged to be suspended in the fluid (200). On the other hand, the system comprises an optical detector (102) of at least a portion of the spectrum of the totally reflected wave (20), said portion including said at least one resonant wavelength(s). A processor is further arranged to determine a presence of said particles (400) on or close to the sensor surface (350) from the frustrated totally internal reflection ("FTIR") signal retrieved from the detected wavelengths, wherein this retrieving takes into account the detected resonant component(s) present in the FTIR signal. The invention relates further to the sensor platform (300) per se, an analyzer and a method.