Lipopolysaccharide (LPS) is a complex molecule composed of lipids and polysaccharides, which mainly exists in the outer membrane of Gram-negative bacteria. LPS consists of lipid A, core oligosaccharides (core), and O-specific polysaccharides or O antigen (Oag), and is fixed to the bacterial outer membrane, with lipid A primarily responsible for its associated toxicity. As a potent activator of pro-inflammatory responses, LPS is involved in a variety of mammalian cells, including macrophages, monocytes, and endothelial cells. While protecting Gram-negative bacteria from environmental stress, LPS also triggers recognition by the innate immune system during infection. This product is supplied as a freeze-dried powder treated with gamma rays. For suspension, add 1 ml sterile equilibrium salt solution or tissue medium to a vial (1 mg) and shake gently until the powder dissolves. After the suspension, the product can be further diluted to the required working concentration using a sterile balanced salt solution or tissue medium.