Cryo-EM Sample Supports and Cooling for Grid Damage Reduction
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Solution Overview
Problem
Current cryo-electron microscopy sample preparation and handling technologies are prone to grid and foil damage, result in poorly controlled sample film thickness, and suffer from issues like crystalline ice formation and sample denaturation, with existing instruments being complex and costly.
Innovation Solution
Innovative sample supports and cooling devices featuring grids with reduced bar width and thickness, marked gripping areas, and automated handling tools, along with liquid nitrogen-based cooling systems that minimize damage and improve cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional grids with standard bar width and thickness are used, then grid strength and durability are maintained, but grid damage during handling and cooling increases
Solution Approach 1:
The patent applies parameter changes by systematically optimizing grid bar dimensions - reducing bar width from traditional 25-50 μm to 10-20 μm, and adjusting thickness to 5-15 μm. These parameter modifications enable the grid to achieve adequate strength while minimizing thermal mass for faster cooling and reducing beam-induced motion, thereby resolving the contradiction between strength and damage resistance
Solution Approach 2:
The patent employs composite materials by combining different metal materials for grid construction - using gold, copper, or nickel for the grid bars and foil, with each material selected for specific properties. This composite approach allows optimization of both mechanical strength and thermal properties, enabling the grid to resist damage while achieving rapid cooling rates
2Ease of operation
If manual handling procedures are used, then operational flexibility is maintained, but grid and foil damage increases
Solution Approach 1:
The patent implements self-service through automated handling systems including robotic pick-and-place mechanisms and automated blotting devices. These systems perform sample preparation tasks autonomously - dispensing sample, blotting excess liquid, and transferring grids - eliminating manual handling steps that cause damage while maintaining operational flexibility through programmable control
Solution Approach 2:
The patent replaces manual mechanical handling with automated mechanical systems. Robotic arms with precision grippers substitute for manual tweezers, automated blotting machines replace manual blotting paper application, and automated transfer systems eliminate manual grid movement. This substitution reduces human error and physical damage while preserving operational flexibility through programmable sequences
3Temperature
If traditional plunge cooling methods are used, then cooling capability is achieved, but crystalline ice formation and sample denaturation occur
Solution Approach 1:
The patent applies parameter changes by optimizing cooling parameters - using liquid nitrogen at 77 K instead of liquid ethane at 90 K, controlling plunge speed to 1-2 m/s, and adjusting sample film thickness to 10-50 nm. These parameter modifications achieve rapid cooling rates exceeding 10^5 K/s while preventing crystalline ice formation and maintaining sample quality
Solution Approach 2:
The patent exploits phase transitions in the cooling process - using liquid nitrogen's phase change from liquid to gas during evaporation to achieve rapid heat extraction. The controlled phase transition enables extremely high cooling rates that vitrify the sample without forming crystalline ice, resolving the contradiction between cooling rate and sample quality
4Manufacturing precision
If complex automated instruments are used, then sample preparation precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies segmentation by dividing the sample preparation process into distinct modular stages - sample dispensing, blotting, freezing, and transfer - each performed by separate automated components. This modular segmentation achieves precise sample film thickness control (10-50 nm) while keeping individual device components simple and manageable
Solution Approach 2:
The patent implements universality through multi-functional automated instruments that combine multiple operations in single devices. For example, automated blotting devices perform both liquid removal and sample flattening, while automated transfer systems handle both grid manipulation and sample positioning. This multi-functionality achieves precise preparation while reducing the number of separate complex instruments needed
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
Simplifies sample preparation, reduces errors, enhances reproducibility, and lowers costs by minimizing grid damage and improving cooling rates while reducing beam-induced sample motion.
Implementation Method 1
the sample-containing foil+grid is plunged at 1-2 m/s into liquid ethane at T ̃90 K (produced by cooling gas in a liquid-nitrogen-cooled cup)
Implementation Method 2
plunged at 1-2 m/s into liquid ethane at T ̃90 K
Implementation Method 3
To vitrify the buffer for the best imaging, the sample-containing foil+grid is plunged at 1-2 m/s into liquid ethane
Data Source
AI summary
Sample support designs and sample cooling devices may be sued for single-particle cryo-electron microscopy. At least some of these sample support design and sample cooling devices help to simplify sample preparation and handling, to dramatically reduce errors and improve outcome reproducibility, and to dramatically reduce overall costs. A cryo-EM system includes, singly and in combination, a grid-based sample support system, grid handling tools, grid blotting tools, a plunge cooling system, and jet cooling systems.