Nanoparticle Sizing via Periodic Illumination and Electric Field Alignment
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Solution Overview
Problem
Conventional methods for measuring nanoparticle properties, such as Nanoparticle Tracking Analysis, face challenges in accurately sizing elongated and irregularly shaped particles due to their blinking behavior and varying light scattering intensity, which leads to incomplete tracking and inaccurate sizing.
Innovation Solution
The method involves reducing the frame rate of video capture to 4 frames per second with increased exposure time and adjusting illumination to minimize blinking, and applying an electric field to align elongated particles, allowing for accurate decomposition of Brownian motion into translational and rotational components for precise sizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If standard video frame rate (30 fps) is used for nanoparticle tracking, then temporal resolution is improved, but particle tracks become incomplete and sizing accuracy deteriorates due to blinking and rapid intensity variations
Solution Approach 1:
The patent applies periodic action by reducing the video frame rate from standard 30 fps to 4 fps, creating a periodic sampling regime that aligns with the characteristic blinking frequencies of elongated nanoparticles. This lower frame rate allows the particle tracking system to capture stable intensity periods between blinking events, thereby obtaining complete particle tracks for accurate Brownian motion analysis and sizing.
2Measurement precision
If high frame rate video capture is used, then motion tracking resolution is improved, but image blurring increases due to particle motion during exposure
Solution Approach 1:
The patent employs periodic action through synchronized illumination that operates in sync with the reduced 4 fps frame rate. The illumination is activated only during the brief exposure window of each frame, creating a periodic on-off pattern that captures particles during stable periods. This synchronization minimizes motion blur while maintaining adequate temporal sampling for Brownian motion analysis.
3Device complexity
If conventional illumination is used for nanoparticle imaging, then setup simplicity is maintained, but blinking artifacts increase due to varying light scattering from elongated particles
Solution Approach 1:
The patent applies parameter changes by modifying the illumination intensity as a function of time, synchronizing it with the reduced frame rate. The illumination intensity is adjusted to provide optimal contrast during the brief exposure windows at 4 fps, compensating for the varying light scattering properties of elongated particles without requiring complex optical systems. This parameter modulation reduces blinking artifacts while maintaining system simplicity.
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 enables the recording of longer particle tracks and reduces image blurring, resulting in more accurate particle size determination and characterization of elongated nanoparticles by analyzing particle size distribution in both parallel and orthogonal directions to the electric field.
Implementation Method 1
the light scattering off the nanoparticles is observed at a right angle
Implementation Method 2
track images of light reflected or scattered by the nanoparticles undergoing Brownian motion
Implementation Method 3
applying an electric field to align elongated particles
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The system includes an adjustable light source constructed to direct a beam of electromagnetic radiation at a specimen chamber that allows a portion of the beam to scatter when illuminating particles within the chamber. The scattered portion of the beam is directed to a sensor, the sensor having a frame rate and a time period between frames. The system may have a processor connected to the sensor and light source, the processor may perform the following steps: activate the light source and obtain images from sensor; if the images from the sensor show that particles are blinking then reduce the frame rate, set the exposure time to at least 60% of the time between frames and reduce the illumination. Then the processor obtains additional images and processes those images to mitigate blurring. The processor determines the Brownian motion of the particles from the processed images and determines the sizes of the particles based on the motion.