Biological Sample Expansion Imaging for Cellular Ultrastructure Resolution
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Solution Overview
Problem
Fluorescence microscopy is limited in revealing cellular ultrastructures due to insufficient optical resolution and the inability to label the entire sample at high density, while electron microscopy requires extensive data acquisition time for three-dimensional imaging.
Innovation Solution
A method involving physical expansion of biological samples by a factor of two or more, combined with bulk labeling using reagents to introduce contrast, allowing for high-density labeling and resolution of fine structures without specific labeling or electron microscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluorescence microscopy is used to label specific proteins, then high contrast imaging is achieved, but the optical resolution is insufficient to reveal fine ultrastructural details
Solution Approach 1:
The patent applies physical expansion to transform the sample from its native scale to an expanded scale (4-10 fold or greater), effectively adding a dimensional transformation that enlarges ultrastructures to be resolvable by light microscopy. This dimensional change allows structures previously invisible at the nanometer scale to become visible at the micrometer scale where optical microscopy operates.
Solution Approach 2:
The patent changes the physical parameters of the sample by expanding its volume and altering its refractive index through embedding in specialized media. This parameter change enables the sample to be imaged with conventional optical microscopes at enhanced resolution, effectively transforming the imaging problem from one requiring electron microscopy to one solvable with light microscopy.
2Measurement precision
If electron microscopy is used to achieve high resolution three-dimensional images, then fine ultrastructural details are revealed, but data acquisition requires days to weeks of continuous imaging
Solution Approach 1:
The patent replaces the mechanical/electronic scanning system of electron microscopy with optical microscopy of physically expanded samples. Instead of using electron beams and complex scanning systems that require days of acquisition, the method uses conventional light microscopy on expanded samples, reducing acquisition time to hours or less while maintaining ultrastructural detail.
3Quantity of substance
If the sample is physically expanded, then bulk labeling at high density becomes feasible, but the sample requires embedding in swellable polymer networks
Solution Approach 1:
The patent introduces swellable polymer networks as an intermediary medium that enables physical expansion of the sample. These polymer networks serve as a bridge between the fixed sample and the expanded state, allowing uniform expansion while maintaining sample integrity and enabling subsequent bulk labeling at high density throughout the expanded volume.
Data Source
Figure 1a~1c
Figure 1d~1g
Figure 1h
AI summary
Methods and systems for physical expansion and imaging of biological samples are described herein. In one aspect of the disclosure, a method for preparing a biological sample for the purpose of generating images of its ultrastructure with an imaging instrument includes a) physically expanding the sample by at least a factor of two in at least one dimension; and b) bulk labeling a plurality of components of the sample with at least one reagent to introduce contrast.