Detergents are all around us in the lab – and that’s a good thing! Thanks to their chemical structure, detergents can solubilize and interact with many types of molecules, making them vital to research. To show you why detergents are such a good thing for scientists, we’ll go through six examples in molecular biology where detergents are essential!
1. Blocking Non-specific Binding
If you’ve ever done immunoassays like ELISAs, you’ve probably used to detergents as chemical blockers. Non-ionic detergents like Tween 20 reversibly block the non-specific binding that could drown out your target’s signal in immunoassays. They also inhibit passive, covalent binding of molecules to the plate, and interfere with protein-protein interactions. However, some detergents like Triton X-100 are too effective – they block and inhibit your target molecule!
2. Cell Lysis
Whether you’re isolating DNA, RNA, or protein, the first step is to lyse cells. Thanks to their solubilizing abilities, detergents are great at disrupting cell and nuclear membranes. Mild, non-ionic or zwitterionic detergents like CHAPS are better for lysing cells when you want to isolate proteins in their native, functional forms. In contrast, harsh ionic detergents like SDS are great when you’re going to do a Western blot with denatured proteins. One downside of using detergents to lyse cells is that they can interfere with Bradford and other protein quantification assays! You can often avoid this problem by using the BCA protein assay, instead.
3. Cell Permeabilization
When you need to stain those inconvenient intracellular markers for FACS, detergents are there for you. But don’t reach for harsh detergents like SDS! A mild membrane solubilizer like Tween 20 or saponin can poke holes just big enough to let antibodies slip into your cells without disintegrating their entire membrane.
4. Gel Electrophoresis
Whether you’re doing native, denatured, or 2D gel electrophoresis (or even isoelectric focusing), there’s a detergent to help you. If you’re not worried about your proteins’ native structure, then a harsh detergent like SDS will solubilize and denature them for SDS-PAGE. But if you need to preserve their structure—isolectric focusing or native electrophoresis—then a gentler, zwitterionic detergent like CHAPS would be a safer bet.
5. Solubilizing and Crystallizing Membrane Proteins
Membrane proteins are tricky things – like detergents themselves, they have hydrophobic and hydrophilic parts. Plus, membrane proteins often need to be embedded in a membrane to preserve their structure and function, making it difficult to isolate and study them! Fortunately, the micelles formed by mild detergents can mimic the properties of the original phospholipid bilayer. For isolating and crystallizing membrane proteins, CHAPS is likely a better choice than Tween or Triton, because CHAPS has a more uniform structure.
6. Washing Your Hands
After all that hard work in the lab with hazardous chemicals (and labmates with runny noses!), protect yourself and others by washing your hands for 30 seconds under running water with a good plain or antimicrobial soap. And keep yourself safe by reading up on lab safety practices.
With their useful abilities, it’s no surprise that detergents play key roles in molecular biology! See below to learn more about detergents, or read up on how they are used to make drug delivery liposomes in medicine!
Garavito RM and Ferguson-Miller S. Detergents as tools in membrane biochemistry. 2001. J Biol Chem. 276:32403–6.
Gibbs J. Effective Blocking Procedures. Corning, Inc. 2001.
Privé GG. Detergents for the stabilization and crystallization of membrane proteins. 2007. Methods. 41:388–397.