Negative staining of lipopolysaccharides on polyacrylamide gels by using eosin B.

A sensitive and simple technique for the negative detection of lipopolysaccharides (LPSs) following polyacrylamide gel electrophoresis (PAGE) using eosin B (EB) was developed. After electrophoresis, gels were fixed, stained, and developed within 30 min to achieve transparent and colorless LPS bands under opaque gel matrix background. As low as 20 to 40 ng of total LPSs could be detected, which is 4-fold more sensitive than those of the widely used silver stain developed by Fomsgaard and coworkers and imidazole-zinc (IZ) negative stain. For its sensitivity and brevity, this stain may be a practical method for LPS determination in the routine laboratory.