The operation process technology of Cryo EM fully automatic liquid nitrogen generation device is mainly used for rapid cooling of samples, so that the samples can maintain their original structure at extremely low temperatures and avoid damage such as water ice crystallization during sample preparation. The following are the typical operating procedures and technical steps of the device:
1. Equipment preparation
Check the equipment status: Ensure that the cryo electron microscope and liquid nitrogen generation device are operating normally, including the liquid nitrogen storage system, gas supply, and temperature control system.
Check the liquid nitrogen level: Confirm that the liquid nitrogen in the liquid nitrogen tank is sufficient and there is no leakage. In general, it is necessary to ensure sufficient liquid nitrogen to ensure the cooling effect throughout the entire operation process.
2. Sample preparation
Sample fixation: Place the sample to be observed on the grid used for cryo electron microscopy. Samples can be protein complexes, viruses, cells, or other biological samples that require freezing.
Sample coating: Apply a thin sample film evenly on the grid to ensure that the sample can be spread evenly and prevent excessive sample thickness from causing opacity or signal attenuation.
3. Start up of liquid nitrogen generation device
Automatic liquid nitrogen gasification: The liquid nitrogen generation device converts liquid nitrogen from liquid to gas through a gasifier for use in the cooling system. Gaseous liquid nitrogen provides continuous low temperature to the sample through pipelines or cooling jackets.
Cooling system activation: Start the cooling system to ensure that the sample quickly reaches low temperature. This process usually sets a target temperature (such as -196 ° C) and a cooling time (such as between a few seconds and a few minutes).
Cooling time monitoring: Liquid nitrogen generation devices are generally equipped with temperature sensors and automatic control systems to monitor the cooling status of samples in real time. Excessive cooling time may affect the quality of the sample, while insufficient cooling time may result in incomplete cooling of the sample.
4. Sample cooling
Rapid cooling: Through a fully automated system, the liquid nitrogen generation device ensures that the sample rapidly cools down upon contact with liquid nitrogen. This process can ensure that the moisture in the sample is quickly converted into amorphous ice, avoiding crystallization and thus maintaining the original structure of the sample.
Temperature control and protection: The liquid nitrogen generation device is generally equipped with a temperature control system, which automatically adjusts the gas flow rate and temperature to ensure uniformity during the sample cooling process.
5. Sample storage and transfer
Frozen sample storage: After the sample is cooled, it can be quickly transferred to a liquid nitrogen tank for long-term storage. The frozen sample can maintain a stable state in liquid nitrogen, avoiding structural changes or degradation.
Sample transfer to cryo electron microscope: Frozen samples need to be transferred to the cryo electron microscope sample stage at extremely low temperatures. Automatic liquid nitrogen generation devices are generally equipped with a rapid transfer system to ensure that the sample does not thaw during the transfer process.
6. Monitoring and Automation
Automated monitoring: Modern cryo electron microscopy fully automatic liquid nitrogen generation devices are generally equipped with real-time monitoring systems that can record data for each step of the operation (such as temperature, time, flow rate, etc.), and can automatically generate reports. These data help researchers understand the details of the sample preparation process.
Alarm system: Equipment is usually equipped with an alarm system. If there is a disruption in liquid nitrogen supply, temperature not meeting standards, or other situations, the system will automatically sound an alarm to ensure safe operation.
7. End operation
Termination operation: After the cooling process is completed, the device will automatically turn off the liquid nitrogen supply, save the temperature and gas flow settings, and ensure convenience for the next use.
Sample removal: After ensuring that the sample has cooled and stabilized, it can be removed from the cryo electron microscopy operating system for further observation or analysis.
key technology
Automation control technology: It achieves precise control of the cooling process, including the amount of liquid nitrogen used, temperature regulation, and time control.
Real time temperature monitoring: Through sensors and control systems, ensure that the sample maintains an appropriate low temperature environment throughout the entire process to avoid sample deterioration.
Safety protection system: Automatic liquid nitrogen generation devices are usually equipped with pressure, flow, and temperature protection functions to prevent equipment failures and operational safety issues.
This operation process can effectively ensure the stability and accuracy of samples in cryo electron microscopy experiments, while reducing the risk of manual operation errors.