Lipopolysaccharide (LPS) is a biological macromolecule secreted by Gram-negative bacteria, the pathogen of respiratory diseases . Lipopolysaccharide is also an outer membrane glycolipid and innate immune response inducer of Gram-negative bacteria . The close packing of LPS molecules in the outer membrane makes the membrane a strong permeation barrier, which protects cells from the entry of many toxic compounds (including many clinically useful antibiotics).