iSCAT Microscopy Illumination Heterogeneity Correction
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Solution Overview
Problem
Interferometric scattering microscopy (iSCAT) measurements are limited by the need to correct for heterogeneous illumination and non-uniform reflectance, which leads to measurement errors and reduced accuracy in determining molecular weight and concentration of particles.
Innovation Solution
A method that involves measuring iSCAT signals, deriving illumination heterogeneity and reflectance profiles, and normalizing the interferometric contrast using these profiles to correct for heterogeneous reference beam characteristics, thereby enhancing the precision of molecular weight and concentration measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If iSCAT measurements are performed without correction for heterogeneous illumination and non-uniform reflectance, then the measurement process is simple and quick, but the measurement precision and accuracy deteriorate due to errors in determining molecular weight and concentration
Solution Approach 1:
The patent applies preliminary action by performing normalization corrections before final measurements. The system pre-calculates illumination heterogeneity maps and reflectance profiles, then applies these corrections to subsequent measurements. This allows the complex correction process to be prepared in advance, making the actual measurement process simpler while maintaining high accuracy.
Solution Approach 2:
The patent introduces intermediary correction factors (illumination heterogeneity maps and reflectance profiles) that mediate between the raw measurements and the final accurate results. These intermediary elements capture the systematic errors caused by heterogeneous illumination and non-uniform reflectance, allowing them to be compensated without fundamentally changing the measurement apparatus.
2Reliability
If conventional iSCAT methods are used with custom-built microscopes and unconventional cameras, then label-free single molecule detection is achieved, but the device complexity and difficulty of operation increase
Solution Approach 1:
The patent applies parameter changes by transforming the complex custom-built microscope system into a standard widefield fluorescence microscope configuration. By changing the operational parameters and illumination modes of conventional microscopes, the system achieves iSCAT functionality without requiring specialized custom-built equipment, thereby improving ease of operation while maintaining detection reliability.
3Ease of operation
If standard widefield fluorescence microscopes are used for iSCAT measurements, then the ease of operation and device availability improve, but the measurement precision deteriorates due to inability to correct for heterogeneous reference beam characteristics
Solution Approach 1:
The patent introduces software-based intermediary correction layers that process the raw data from standard microscopes. By inserting normalization steps that account for illumination heterogeneity and reflectance variations, the system bridges the gap between the simplicity of standard microscopes and the precision requirements of iSCAT measurements.
Solution Approach 2:
The patent replaces complex mechanical/optical correction systems with computational methods. Instead of using specialized hardware to correct for heterogeneous illumination, the system uses software algorithms to normalize the reference beam characteristics, substituting mechanical complexity with computational processing.
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 improves the accuracy of molecular weight and concentration determinations by accounting for illumination and reflectance variations, leading to more precise measurements of particles in solutions.
Implementation Method 1
iSCAT measures interference contrast between (a) light reflected at the interface between a sample carrier and the sample solution (reference beam) and (b) light scattered by molecules in the sample solution attaching to the sample carrier (sample beam)
Implementation Method 2
light scattered by molecules in the sample solution attaching to the sample carrier (sample beam)
Data Source
AI summary
A method comprising the steps of: measuring a first series of interferometric scattering microscopy (iSCAT) signals and a second series of iSCAT signals of a sample on a sample holder, the sample comprising a particle dissolved in solution; deriving an illumination heterogeneity for the first series of iSCAT signals; deriving a reflectance profile for the first series of iSCAT signals based on the illumination heterogeneity and/or the second series of iSCAT signals; measuring a third series of iSCAT signals of the sample on the sample holder; and normalizing an interferometric contrast for the third series of iSCAT signals with the reflectance profile.