SDS

(SDS) is an organic compound which has the molecular structure found in Figure 2. It is an anionic surfactant that consists of a mixture of sodium alkyl sulfates and appears as a white powder in solid form. As is the case with any surfactant, it is used to lower the surface tension of aqueous solutions 12. The applications of SDS range from its industrial uses in cleaning and hygiene products to its laboratory uses in the study of the biochemistry of proteins. Over the past decade, the uses of SDS have expanded from the chemical industry to being found within many aspects of everyday life. Primarily, SDS is found in detergents used for cleaning and laundry where the removal of oily residues is required. Due to its molecular structure, it has an amphiphilic characteristic that makes it ideal for these uses. It is also employed for other uses in the cosmetic and pharmaceutical industries.
The usage of SDS in a laboratory is as a research tool in the biochemistry of proteins. When SDS is introduced to a protein it causes it to unfold, or denature. Denaturation is a process in which a protein loses its native structure due to the presence of an organic compound. The protein unfolding occurs as the negatively charged SDS bonds to it causing electrostatic repulsion and disruption of the proteins non-covalent bonds 13.
Much research has been done on the fluorescent properties of protein encapsulated gold nanoparticles and how those properties vary with pH-induced protein unfolding. However, the same cannot be said for the usage of a surfactant such as SDS in Gold nanocluster spectroscopy. What work has been done with SDS in using it to cause denaturation has been looking at how it affects the properties of pure proteins when they unfold without the presence of gold clusters 14. When SDS is used in increasing concentrations to unfold BSA, the fluorescence emission intensity of a probe is observed to react differently depending on how much SDS is present and therefore depends on what state the proteins structure is in.