Ion Beam Surface Hydration for Uniform Cryo-EM Sample Ice
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Solution Overview
Problem
Current cryo-EM sample preparation techniques result in preferred particle orientation and deformation due to air-water interface interactions and ice formation, leading to suboptimal structural heterogeneity and low particle density on EM grids, limiting resolution and computational efficiency.
Innovation Solution
A method using a single ion beam from a mass spectrometer to deposit analyte particles and generate an amorphous ice layer on a substrate, eliminating the need for a separate solvent source and improving sample quality by ensuring random orientation and uniform ice thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional sample preparation techniques are used, then particles can be deposited on the EM grid, but particles exhibit preferred orientation and deformation due to air-water interface interactions
Solution Approach 1:
The patent replaces the conventional mechanical blotting and air-water interface drying process with ion beam deposition. The ion beam delivers particles directly to the substrate in a vacuum environment, eliminating the mechanical blotting step and the harmful air-water interface that causes preferred orientation and deformation.
Solution Approach 2:
The patent uses a vacuum environment for ion beam deposition instead of atmospheric conditions. This inert environment prevents air-water interface interactions and maintains particle structural integrity during the deposition process, avoiding preferred orientation and deformation.
2Reliability
If conventional vitrification methods are used, then an ice layer is formed to protect samples, but ice thickness is non-uniform with thinner ice at hole centers
Solution Approach 1:
The patent replaces conventional vapor deposition or blotting-based vitrification with ion beam deposition. The ion beam provides precise control over ice layer formation, enabling uniform thickness across the entire substrate surface including hole centers, while still providing adequate protection from radiation damage.
3Quantity of substance
If highly concentrated samples are used to compensate for particle loss during blotting, then more particles are available, but particles preferentially absorb to the EM-grid substrate
Solution Approach 1:
The patent replaces the blotting process with ion beam deposition, which delivers particles directly to the substrate without the blotting step that causes preferential absorption to grid edges. This results in more uniform particle distribution and better hole occupancy even at high concentrations.
4Productivity
If conventional preparation techniques are used, then samples can be imaged, but data acquisition time is extended and computational resources are strained due to low particle density
Solution Approach 1:
The patent replaces conventional preparation with ion beam deposition, which achieves high particle density on the substrate. This high density reduces the number of grid areas that need to be imaged to collect sufficient particles, thereby reducing data acquisition time and computational strain for 3D reconstruction.
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 simplifies the sample preparation process, reduces costs, and enhances the quality of cryo-EM samples by achieving a high density of randomly oriented particles with uniform ice thickness, thereby improving data acquisition efficiency and reducing computational strain.
Implementation Method 1
a) forming an analyte beam from the analyte solution, wherein the analyte beam comprises charged or uncharged analyte particles and molecules of the solvent; b) directing the analyte beam toward a substrate surface such that the charged or uncharged analyte particles and molecules of the solvent impinge on the substrate surface
Implementation Method 2
an amorphous solid layer of the solvent is formed on the surface of the substrate, wherein the charged or uncharged analyte particles are embedded on or within the deposited amorphous solid layer
Implementation Method 3
Surface Hydration with an Ion Beam
Data Source
AI summary
Systems and methods for controllably forming an analyte layer comprising amorphous ice and/or other frozen amorphous solids on a substrate. In an embodiment, the present invention provides simplified systems and methods for the preparation of cryo-EM samples, where the same particle beam, such as an ion beam, is used to deposit the desired analyte onto the substrate as well as to generate the amorphous ice or frozen solid layer on the substrate