Eli5: What is the difference between silver sulfadiazine and “colloidal silver?”

Question

I know that the consensus on colloidal silver is that it is pseudoscience quackery, but I’m just wondering why that is. If silver is used as an antimicrobial in medical settings, what is it about colloidal silver that makes it so ineffective as a topical antimicrobial?

Thank you!

In: Chemistry

Answer 1

I don’t know the details, but the silver is different. Colloidal silver is a colloid, so it’s silver molecules or particles suspended in water. Silver sulfadiazine is a coordinating complex with silver (I) or Ag^+ ion. The charged ion form kills bacteria and the uncharged molecular form doesn’t, so my guess is that’s why colloidal silver doesn’t work.