Nanoparticle Tracking Analysis with Perpendicular Flow Velocity Estimation
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Solution Overview
Problem
Nanoparticle tracking analysis (NTA) faces challenges in accurately determining particle size due to the difficulty in distinguishing between Brownian motion and flow-induced motion, especially at higher flow rates or concentrations, leading to errors in particle tracking and size measurement.
Innovation Solution
The apparatus and method employ 1-dimensional particle tracking in a direction perpendicular to the expected flow direction to estimate flow velocity, followed by correction and subsequent 2-dimensional tracking to minimize errors, using a tracking distance limit to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If 2-dimensional particle tracking is used to identify particles in subsequent frames, then particle tracking can be performed, but unacceptable errors occur in identifying particles when flow rate and concentration increase
Solution Approach 1:
The particle tracking process is segmented into two distinct phases: first, 1-dimensional tracking perpendicular to flow direction is used to estimate flow velocity; second, 2-dimensional tracking is performed with flow correction applied. This segmentation allows each tracking phase to optimize for its specific purpose, improving overall accuracy.
Solution Approach 2:
Flow velocity estimation is performed as a preliminary action before the main particle size measurement tracking. By first determining the flow velocity through 1-dimensional tracking and then correcting for this flow in the subsequent 2-dimensional tracking, the system prepares the data in advance to eliminate flow-induced errors from the final measurements.
2Measurement precision
If a flow of sample is provided to improve measurement accuracy and sweep contaminants, then more sample is analyzed, but it becomes difficult to determine when tracking accuracy falls below acceptable levels
Solution Approach 1:
The system implements feedback by continuously monitoring particle tracking quality metrics and comparing them against acceptance criteria. The computer evaluates whether tracking accuracy remains above acceptable thresholds and can identify when flow rate or concentration increases cause degradation, allowing real-time assessment of measurement reliability.
3Productivity
If flow rate and concentration are increased to analyze more sample, then productivity improves, but the ability to distinguish Brownian motion from flow-induced motion deteriorates
Solution Approach 1:
Flow velocity is estimated in advance through 1-dimensional tracking perpendicular to the flow direction, before the main particle size measurements are taken. This preliminary flow characterization allows the system to compensate for flow effects during subsequent 2-dimensional tracking, enabling accurate measurements even at higher flow rates and concentrations.
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 enhances the accuracy of particle size determination by reducing misidentification and improving the estimation of flow velocity, thereby correcting for drift and enhancing the precision of particle size measurements.
Implementation Method 1
collect light scattered or fluoresced by particles moving within the flow cell
Implementation Method 2
collect light scattered or fluoresced by particles moving within the flow cell
Implementation Method 3
tracking the movement of individual particles and determining the size of the particles based on their Brownian motion
Data Source
AI summary
The present invention provides an apparatus for characterising particles using nanoparticle tracking analysis (NTA). The apparatus comprises: a flow cell for containing a sample comprising a plurality of particles suspended in a fluid; a pump configured to provide a flow of the sample through the flow cell; a light source configured to illuminate the sample; an imaging system configured to collect light scattered or fluoresced by particles moving within the flow cell and within a detection region of the imaging system, and capture a video of the particles moving within the detection region; and a computer configured to process the video. The computer is configured to determine an estimated flow velocity of the sample through the flow cell. Determining the estimated flow velocity comprises performing 1-dimensional particle tracking in a direction perpendicular to an expected flow direction of the sample.