Forget Surgical Steel, give me Surgical Copper!
I was using the downtime during this time of year to catch up on some reading. In the Machine Design trade magazine there was an interesting article that caught my eye. Testing of copper as an anti-microbial surface. The comparisons with stainless steel are interesting, because most of the metal surfaces in an operating room are stainless of some sort (304 or 316 stainless).
E. coli, a food-born pathogen, that in the elderly and children can lead to life-threatening hemolytic uremia syndrome, was one of the first bacteria tested. Room-temperature results showed that on pure and 99%-copper substrates extremely high levels of the bacteria dropped two orders of magnitude in only 45 min and were completely gone in 75 min. There was a similar pattern at 4°C (39°F). It took between 75 and 180 min for a drop in bacterial counts from 100 million to total eradication.
It even seems effective against MRSA (Methicillin resistant Staphylococcus aureus), the bane of hospitals everywhere.
I was aware that copper was toxic to living cells, mostly through design work where biocompatibility was tested, but the mechanism was news to me. Copper’s toxicity to cells comes from the Oligodynamic effect, where some metal ions demonstrate this toxicity. The mechanism is not yet understood, but possibly the cause is the denaturing of the bacteria’s proteins. Silver also demonstrates this effect, and this is why it is used in the treatment of burns via silver nitrate impregnated gauze (something else I can attest to).
I wonder if more of the touch surfaces in hospitals and operating rooms will be designed with at least a minimum amount of copper, with that minimum determined by an effectiveness at killing bacteria. There is also the question of allergic reactions, the effect of oxidation, or the allowable contact time before there is a noticeable effect on healthy tissues.
