July, 2021

The door handle may be the handshake of a building, but handshakes are currently out and ‘elbow bumping’ a door is unlikely to have the desired effect. Reducing transmission is clearly an important part of learning to live with coronavirus and ferocious chemical spritzes and single-use PPE cannot be a long-term solution. Understanding materials and their inherent antimicrobial properties can help make it safe to open doors again, enabling the return of tactile interactions with our surroundings that have been sorely missed during the pandemic.

Historically, doorknobs and handles have been made out of bronze or brass, which are both copper alloys. Copper has powerful natural antimicrobial properties; Smithsonian Magazine describes how it is capable of killing micro-organisms by blasting them with ions ‘like an onslaught of missiles’ that punch holes in cell membranes or viral coatings before destroying the DNA or RNA inside. Most importantly of all, the article claims, it is this destruction of the genetic material that prevents ‘the mutations that create drug-resistant superbugs.’

This remarkable phenomenon has been recognised for millennia – the Ancient Egyptians used copper to cure infections; whisky has been made in copper stills since at least 800AD for the same reason. Bill Keevil, a microbiology researcher at the University of Southampton, has done tests on the century-old copper railings at New York’s Grand Central Station which have shown that the antimicrobial effect doesn’t fade with time and use. Some of Keevil’s most recent research has compared how coronaviruses are zapped within minutes of landing on a copper or copper alloy surface, but remain infectious for days on glass or stainless steel.

Since the 60s, contemporary architects have tended to favour Stainless steel architectural ironmongery for its clinical appearance and lack of tarnish. In reality it provides a hospitable resting place for microbes, Covid-19 coronaviruses included. Counterintuitively, both the dull patina of age or the caramel polish of frequent use should be read as reassurance of bronze and brass’s cleanliness, and not a warning sign of contamination.

 

Miranda Vane