What is diafiltration?

Diafiltration is a process used in the purification and concentration of biomolecules, such as proteins, peptides, and nucleic acids. It involves the continuous exchange of buffer solution with the retentate (concentrated biomolecule solution) to remove impurities and salts, while also concentrating the biomolecule of interest.

During diafiltration, the retentate is subjected to tangential flow filtration, in which the solution flows parallel to the membrane surface and particles larger than the membrane pores are retained. The permeate, which contains impurities and salts, is continuously removed and replaced with fresh buffer solution. This helps to maintain a constant volume and ensure efficient removal of impurities.

Diafiltration can be performed using various types of membranes, such as ultrafiltration or nanofiltration membranes, depending on the size of the biomolecule and the molecular weight cutoff required. It is commonly used in downstream processing of biopharmaceuticals, as well as in the food and beverage industry for the purification and concentration of proteins and enzymes.