Endotoxin filter is one of the commonly used four types of filters that are used for removing toxins like endotoxins from biological mixtures like the mixture of glucose and saline water. At this stage, a question arises that what an endotoxin is?
Introduction with Endotoxin
Endotoxins are LPS or lipopolysaccharides found in the wall of the cell of gram-negative bacteria that do not retain the stains of crystal violet shade in the process of differentiation of bacteria. When these bacteria die endotoxins are consistently shed by the walls of their cells. These endotoxins are necessary to be removed as they are contaminants in the preparation of plasmid. The toxicity caused by endotoxins can interfere while examining the cells so they must be removed from the research samples by using an endotoxin filter.
The Necessity to Remove Endotoxin
It is necessary to remove endotoxin from the research samples as they can contaminate the expressed protein and plasmid-based preparations when gram-negative bacteria are used for recombining various genetic materials, cells or organisms. These complicated endotoxins have to be removed before conducting any examination like developing a manufacturing process or reading out immunologic. You can also use the endotoxin filter to capture intact bacteria as they can be more challenging during an examination. You can also use a substrate with a positive charge to remove the negatively charged LPS effectively.
For Removal of Endotoxins from Biological Solutions
Endotoxin filter can also be used for removing endotoxins from biological solutions like neutral sugars and water buffers etc. An Endotoxin is a complex combination of LPS or lipopolysaccharides of acidic nature which includes a=the innermost core of the fatty acid of hydrophobic groups as well as the outermost and central region containing hydrophilic polysaccharides.
In a watery solution, you can find endotoxin in various types of combinations. Mg2+ and Ca2+ are some of the divalent elements that can be used to stabilize the LPS in aggregated form whereas this structure can be split into small units by using detergents. So it becomes necessary to use endotoxin filter to remove endotoxins from the end product while producing a combination of protein with gram-negative bacteria as the presence of endotoxin can give wrong reading while examining the cells while developing a manufacturing process and reading out immunologic. In human-related products, the endotoxins should not be present more than a specific limit.
Reasons for Contamination of Endotoxin
The outer membrane of the workable gram-negative bacteria consistently shed endotoxin which is also released by the wall of bacterial cells when cells are dead. Though you can use sterilizing grade filter to remove bacteria but it is difficult for this filter to remove or inactivate LPS because its pH is stable and it is extremely hot.
Similarly, during the downstream processes while purifying protein the removal of endotoxin is difficult without an endotoxin filter. Endotoxin cannot be removed satisfactorily by using a number of commercial filters available in the market as incubation of endotoxin is a time-consuming process.
Thus, the complete removal of endotoxin can be achieved only by losing substrate massively unless an endotoxin filter is used.