Dialysis tubing is a commonly used tool in laboratories for research in fields such as biochemistry, molecular biology, and biotechnology. Its main function is to allow the passage of small molecules and prevent the passage of large molecules through the principle of semi-permeable membranes, so as to achieve the separation, purification and concentration of samples. The following are the specific uses and functions of dialysis tubing in the laboratory.
1. The basic principle of dialysis bags
A dialysis tubing is a tubular vessel made of a semi-permeable membrane, and its pore size can be selected according to your needs. When a sample is placed in a dialysis tubing and immersed in the corresponding solution, the small molecules in the sample can freely enter and exit the tubing due to the selective permeability of the semipermeable membrane, while the large molecules are trapped in the bag. By constantly changing the external solution, the sample can be separated, purified, and concentrated.
2. Application of dialysis tubing in the laboratory
1.Sample desalting: Dialysis tubing can be used to remove salts from samples. The sample is placed in a dialysis tubing and immersed in a low-salt or salt-free solution, and the salts in the sample can be gradually removed by constantly changing the solution, resulting in a purified sample.
2.Changing the sample buffer: Dialysis tubing can also be used to change the buffer for the sample. The sample is placed in a dialysis tubing and immersed in the required new buffer, which can be quickly changed through the action of a semi-permeable membrane.
3.Sample concentration: Dialysis tubing can be used for sample concentration. The sample is placed in a dialysis tubing and immersed in a solution containing a lower concentration, and through the action of a semi-permeable membrane, the water in the sample gradually penetrates into the external solution, thus achieving the concentration of the sample.
4.Protein renaturation: After protein crystallization or precipitation, dialysis tubing can be used for protein renaturation. The precipitated or crystallized protein is placed in a dialysis tubing and soaked in an appropriate refolding solution, which can gradually return the protein to its native state through the action of a semi-permeable membrane.
3. Precautions for use
1.Choose the right dialysis tubing pore size: Choose the appropriate dialysis tubing pore size based on the molecular weight and needs of the sample to ensure separation.
2.Avoid over-concentration: When concentrating samples, care should be taken to avoid over-concentration that can lead to sample denaturation or precipitation.
3.Replace the external solution regularly: During dialysis, the external solution should be changed regularly to ensure the separation effect.
4.Cleaning and storage: Dialysis tubing should be cleaned and stored in appropriate conditions for next use.