Twenty seconds of scrubbing with soap are one of the best ways to protect yourself – from people and objects – from germs that cause disease. But how do soapy suds kill pathogenic bacteria and infectious bacteria?
The supernatural power of the soap is filled with bacteria built into its molecular structure: a “head” attached to a long “tail,” according to Drs. Lee Riley, physician, professor, and chair of the Division of Infectious Disease and Vaccinology at the University of California. (U.C.) Berkeley. The head is hydrophilic or water-loving, and the tail is hydrophobic – water-repellent or dehydrated. That hydrophobic tail is oil-related, and all bacteria and viruses – including SARS-CoV-2, the coronavirus that causes the disease COVID-19 – have a lipid membrane, which leaves them at risk for the tail-soap-puncturing molecule.
“The tail attaches itself to the lipid [bacterial] layer, and thus ends up being killed,” Riley told Live Science.
Some species of bacteria have strong cell walls, so they can survive even after the hydrophobic soap tail enters its membrane. But even in these cases, soap bubbles can defeat the bacteria and viruses around them and separate them.
When the soap attacks these germs, the tails in the soap molecules attach to the lipid membrane of the cell, and the hydrophilic heads face outwards. This forms a small ball of soap particles, known as a micelle, that surrounds the pathogen, Drs. John Swartzberg, a doctor, clinical professor, and infectious disease specialist at UC Berkeley, told Live Science. Micelles easily catch germs or germs because the outside of the micelle is hydrophilic, so it is easily swept away from your hands and down a ditch – and its pathogens – when you clean soap with water.