Freezable Fluid Cell for Cryo-EM Ice Thickness Control
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Solution Overview
Problem
Cryo-electron microscopy sample preparation methods using robotic blotting result in variable ice thickness and concentration gradients, leading to inconsistent background noise and hindering automation in high-resolution imaging.
Innovation Solution
A freezable fluid cell system with electron-transparent materials and a planar regime for sample freezing, eliminating air-liquid interfaces and enabling uniform ice thickness, facilitating automated imaging by reducing noise and improving protein distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If robotic blotting methods are used to prepare cryo-EM samples, then sample preparation can be automated, but the ice thickness becomes variable and concentration gradients occur
Solution Approach 1:
The device segments the sample preparation process into distinct functional zones: a loading zone for sample introduction, a compression zone with controlled air-liquid interface for uniform ice formation, and an imaging zone. This segmentation allows each zone to perform its specific function optimally, ensuring uniform ice thickness while maintaining automation capability.
Solution Approach 2:
The device controls and optimizes critical parameters including air pressure applied during compression, temperature during freezing, and the geometry of the compression chamber. By precisely controlling these parameters, the device achieves uniform ice thickness and eliminates concentration gradients that plague traditional blotting methods.
2Ease of manufacture
If traditional blotting methods are used, then sample preparation is simpler, but background noise becomes inconsistent across the sample
Solution Approach 1:
The device introduces a controlled air-liquid interface as an intermediary element during the compression phase. This intermediary allows for precise control of the freezing process, ensuring that the ice forms uniformly across the entire sample area, thereby producing consistent background noise levels throughout the imaged region.
3Measurement precision
If manual screening is performed to locate suitable imaging regions, then image quality can be improved, but time consumption increases significantly
Solution Approach 1:
The device is designed to automatically produce uniformly high-quality ice across the entire imaging area, eliminating the need for manual screening to locate suitable regions. The self-service nature of the device ensures that every region of the sample meets imaging criteria, allowing immediate transition to automated data collection without time-consuming manual evaluation.
4Ease of operation
If air-liquid interfaces are present in the sample, then sample preparation is easier, but three-dimensional structure determination is hindered
Solution Approach 1:
The device extracts and eliminates air-liquid interfaces from the final vitrified sample structure by controlling the freezing process within a sealed compression chamber. The sample is compressed and frozen in the liquid state, preventing air-liquid interface formation that would otherwise interfere with three-dimensional structure determination, while maintaining ease of operation through automated 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
The system achieves consistent ice thickness and reduced noise, allowing for automated high-resolution imaging and improved data quality by eliminating air-liquid interfaces and ensuring uniform protein distribution within the sample.
Implementation Method 1
an aqueous droplet containing a biological sample is introduced into an inlet port of the freezable fluid cell, in which the biological sample is pulled into the device by capillary action
Implementation Method 2
The freezable fluid cell is then rapidly cooled to immobilize the biological sample in a thin film of ice
Data Source
AI summary
A system and method for imaging a biological sample using a freezable fluid cell system is disclosed. The freezable fluid cell comprises a top chip, a bottom chip, and a spacer to control the thickness of a vitrified biological sample. The spacer is positioned between the top chip and the bottom chip to define a channel that is in fluid communication with an inlet port and an exit port to the freezable fluid cell system. The channel can be filled with a biological sample, vitrified, and imaged to produce high-resolution electron microscopic image.