Quantitative Phase Microscopy for Label-Free Cell Imaging
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Solution Overview
Problem
Conventional microscopy techniques face challenges in providing sufficient contrast for reliable automated segmentation of cell bodies and nuclei, especially in live cells, and lack quantitative thickness information for cell monolayers, often requiring staining or labeling that can alter sample properties.
Innovation Solution
A tunable phase-contrast imaging system that uses a low coherence light source and optical elements to collect and manipulate diffracted and undiffracted light, producing quantitative phase images with sufficient contrast for label-free segmentation and thickness information, employing a movable mirror for relative phase shifts and spatial filtering to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If staining or labeling techniques are used to enhance contrast, then image contrast is improved, but the sample structure or properties are altered and live cell imaging is not possible
Solution Approach 1:
The patent introduces phase modulation as an intermediary mechanism between the light source and sample. A phase plate modulates the phase of undiffracted light, creating interference patterns that enhance contrast without requiring physical contact with or alteration of the sample. This mediator (phase plate) enables contrast enhancement while preserving sample integrity and enabling live cell imaging.
Solution Approach 2:
The patent changes the optical parameter of light phase rather than altering sample properties. By modulating the phase of undiffracted light and creating interference with diffracted light, the system achieves contrast enhancement through optical parameter manipulation instead of chemical or physical sample modification, allowing live cell imaging.
2Illumination intensity
If conventional phase-contrast imaging is used, then image contrast is improved without staining, but additional optical components and alignment procedures are required
Solution Approach 1:
The patent integrates the phase modulation function into the existing microscopy optical path using components that serve multiple purposes. The phase plate can be positioned at the focal plane of the objective lens, utilizing the existing focal structure for phase modulation while maintaining compatibility with standard microscopy configurations, thereby reducing the need for separate alignment procedures.
3Device complexity
If conventional optical imaging is used, then imaging is simple, but quantitative thickness information is not provided
Solution Approach 1:
The patent employs interferometry to create feedback between the undiffracted and diffracted light paths. The phase modulation creates interference patterns that encode quantitative information about sample thickness and refractive index variations. By measuring the interference pattern, the system retrieves quantitative thickness information while maintaining a relatively simple optical configuration.
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 system achieves high-contrast, label-free imaging and quantitative thickness information, enabling reliable automated segmentation of cells and nuclei without altering the sample, as demonstrated by its ability to accurately measure sample thickness and differentiate cellular structures.
Implementation Method 1
the light source produces a beam of light with low coherence. The light may have a coherence length of less than 10 microns.
Implementation Method 2
the at least one main beam optical element is configured to collect light diffracted by the sample and to collect light not diffracted by the sample
Implementation Method 3
The mask may be configured to block most of the first diffracted beam and to transmit most of the focused first undiffracted beam. Generally, the mask filters modulation components from the undiffracted beam, which provides a clean phase reference.
Implementation Method 4
The movable mirror is configured to be positioned to produce each of a plurality of selected phase-shifts in the first beam relative to the second beam
Implementation Method 5
a beam splitter configured to split the light collected by the at least one main beam optical element into a first beam and a second beam
Data Source
AI summary
Systems and methods described herein employ multiple phase-contrast images with various relative phase shifts between light diffracted by a sample and light not diffracted by the sample to produce a quantitative phase image. The produced quantitative phase image may have sufficient contrast for label-free auto-segmentation of cell bodies and nuclei.