Vibrating Needle Welding Cryogenic Biological Samples
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Solution Overview
Problem
Existing methods for welding a sample to a microprobe often result in the sample losing its vitrified condition due to heat capacity issues or require complex equipment like ion beam columns and gas injection systems.
Innovation Solution
The method involves vibrating the microprobe's extremity to locally melt the sample, allowing it to freeze to the extremity when vibration stops, using a vibrating metal needle at cryogenic temperatures, and performing the process in an evacuated chamber to maintain the sample below its glass transition temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the extremity is temporarily heated to a temperature above the melting point of water, then the sample can be welded to the extremity, but a part of the sample melts or loses its vitrified condition
Solution Approach 1:
The patent applies mechanical vibration to the extremity to generate localized friction heat when contacted with the frozen sample. This vibration-based heating method concentrates energy precisely at the contact interface, enabling welding while minimizing thermal diffusion to surrounding areas, thus preserving the vitrified condition of the bulk sample.
Solution Approach 2:
The invention creates a localized heating zone at the extremity-sample contact point through vibration. The heating is highly localized to only where the extremity touches the sample, allowing the rest of the sample to remain frozen and vitrified while still achieving reliable welding at the contact point.
2Reliability
If resistive heating or laser beam heating is used to heat the extremity, then welding can be achieved, but a larger part of the sample melts due to heat capacity of the heated extremity
Solution Approach 1:
The patent replaces resistive or laser heating with mechanical vibration of the extremity. This vibration generates heat locally through friction at the contact point, avoiding the heat capacity problem of bulk heating methods. The extremity itself does not need to be heated, only the contact interface, dramatically reducing the amount of sample that melts.
Solution Approach 2:
The invention substitutes thermal heating methods (resistive heating, laser heating) with a mechanical vibration method. This replacement eliminates the need to heat the entire extremity, confining thermal effects to the immediate contact zone and minimizing sample melting.
3Reliability
If ion beam column and gas injection system are used for welding, then sample attachment can be achieved, but the device complexity increases
Solution Approach 1:
The patent extracts the welding function from complex equipment systems (ion beam column, gas injection system) and implements it through a simple mechanical vibration mechanism. This extraction simplifies the overall device while maintaining welding capability, as the vibration method requires only a motorized actuator rather than sophisticated beam or gas delivery systems.
Solution Approach 2:
The vibration-based welding method is self-contained and does not require external support systems like gas injection or ion beam generation. The extremity itself generates the necessary heat through its own vibration, eliminating the need for additional complex equipment.
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 effectively attaches vitrified biological samples to a microprobe while maintaining a significant portion of the sample in a vitrified state, avoiding the need for complex equipment and minimizing heat-induced sample melting.
Implementation Method 1
By vibration of the extremity the extremity and the frozen sample are rubbed over each other. This rubbing causes the frozen sample to locally melt.
Implementation Method 2
the local melting is achieved by vibration of the extremity, the locally melted sample freezing to the extremity when the vibration is stopped
Implementation Method 3
the heat induced by the rubbing is transported away quickly, most of it in the part to which the extremity borders and that is kept to a low temperature
Implementation Method 4
the locally melted sample freezing to the extremity when the vibration is stopped
Data Source
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AI summary
The invention relates to a method of welding a vitreous biological sample at a temperature below the glass transition temperature of approximately -137°C to a micromanipulator, also kept at a temperature below the glass transition temperature. Where prior art methods used IBID with, for example, propane, or a heated needle (heated resistively or by e/g/ laser), the invention uses a vibrating needle to locally melt the sample. By stopping the vibration, the sample freezes to the micromanipulator. The heat capacity of the heated parts is small, and the amount of material that stays in a vitreous condition thus large.