A method for rapid and sensitive negative staining of proteins in SDS-PAGE using 2′,7′-dichlorofluorescein

We report here a rapid and sensitive technique for negative visualization of protein in 1-D and 2-D SDS-PAGE by using 2′, 7′-Dichlorofluorescein (DCF), which appeared as transparent and colorless bands in an opaque gel matrix background. For DCF stain, down to 0.1-0.2 ng protein could be easily visualized within 7 min by only 2 steps, and the staining is 4-fold more sensitive than that of Eosin Y (EY) negative stain and glutaraldehyde (GA) silver stain, and 8-fold more sensitive than that of the commonly used Imidazole-zinc (IZ) negative stain. Furthermore, DCF stain provided good reproducibility, linearity and MS compatibility compared with those of IZ stain. In addition, the potential staining mechanism was investigated by colorimetric experiment and molecular docking, and the results demonstrated that the interaction between DCF and protein occurs mainly via van der waals force, electrostatic interaction and hydrogen bonding. This article is protected by copyright. All rights reserved