LPS (Lipopolysaccharide) neutral solution is left at room temperature for several months without significant changes in its biological activity, and its biological activity can be maintained for years to decades in 4 or cryogenic freezers. Freeze-dried LPS neutral powder that can be left at room temperature or in the refrigerator for decades or more without losing its biological activity.
Bacterial LPS has strong heat resistance, and general autoclaving cannot inactivate it, and 115 30 min of moist heat can only destroy about 25% of endotoxin activity. Endotoxin can be deactivated by ethylene oxide at 50% relative humidity. When the aqueous solution of LPS was treated at different temperatures, it was found that endotoxin activity could still be detected at 200 1 h, and the activity disappeared completely when further heated to 250 30 45 min, or 180 3 4 h. China's 2000 edition of the Pharmacopoeia Endotoxin Inspection Law stipulates that the pyrogen treatment of glassware is 250 dry baking for more than 1 hour.
Partial degradation of LPS in acidic solution at room temperature is mainly caused by cleavage of the glycosidic bond between the core polysaccharide and Lipid A, which can be accelerated under heating conditions. In 0In 1N acetic acid, 100, 45min can make LPS lose 90% of its biological activity. Under heating conditions, a strong acid solution can completely destroy the LPS molecules. 50% citrate (pH 1.)0) Hydrolyzes reactive groups such as phosphate groups or hydroxyl fatty acids of lipid a. The alkaline factor mainly leads to the hydrolysis of the phosphate ester bonds and fatty acid ester bonds attached to the Lipid A backbone, which destroys the Lipid A structure and leads to the inactivation of LPS molecules. Therefore, LPS should be stored under neutral low temperature conditions.
After prolonged (48h) and large doses of CO60 irradiation, the structure of LPS can be completely destroyed. If possible, for experimental equipment that cannot be treated with dry baking, LPS can be removed by long-term and high-dose irradiation.
Hydrogen peroxide is a strong oxidizing agent, which has the functions of antiseptic, sterilization, deodorization and cleaning. After its decomposition, it can release a large amount of new ecological oxygen, which can oxidize and decompose LPS. Hydrogen peroxide mainly cleaves the phosphate group at the C1 position of the reduced end of Lipid A in LPS. The toxicity of Lipid A of monophosphate is significantly weaker than that of Wild-type LPS, which is consistent with the reduction of toxicity after the degradation of LPS by hydrogen peroxide.
The results showed that chloride lime solution (containing 5000mg L available chlorine) could inactivate more than 95% of LPS activity in 20 mg for 30min and chloramine T solution (containing 5000mg L available chlorine) for 20 min for 70min. Under the condition of 60 heating, it only takes 40min for the same amount of endotoxin to be inactivated by chloramine T2% acidic potassium permanganate for 2min, 10% neutral potassium permanganate can inactivate more than 95% of LPS for 160min.