I’ve always heard that brass door knobs are best because they’re “naturally anti-microbial”. How is that possible?
In: Biology
The active antimicrobial ingredient in brass is the copper, which wreaks havoc when bacteria come in contact with it. While the exact mechanisms remain obscure, we can see damage to the cell membrane and interference with key metabolic functions inside the cell.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7999369/
Most metals are antimicrobial to [some extent](https://en.m.wikipedia.org/wiki/Oligodynamic_effect) because metal ions easily make their way into microbes and they usually aren’t very good for living things – they can disrupt biological processes, damage DNA, or create other substances that also do these things.
However, metal also has some problems: they form a thick rust coating negating this benefit (Al), are poisonous to humans (Ni) or are too expensive (Pt). Copper-based alloys, like brass, tend to have the least problems, forming a thin enough rust layer and being suitably affordable, effective and safe, which is why they’re most prevalent.
How/Why is brass antimicrobial ?
byu/rafeykashan inaskscience
Microorganisms generally have a very hard time dealing with copper ions, and brass contains a lot of copper. Brass is used rather than pure copper because it is cheaper and can be made much more resistant to tarnishing and corrosion.
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