One of the key benefits of Affimer technology is that it is tough. Really tough. You can stick them onto gold, glass or plastic and leave them for days, weeks or in some cases months, and they still work. But can they survive the Tough Mudder challenge?
The Tough Mudder is a 12-mile army style assault course involving (you might have guessed) lots and lots of mud: 500,000 litres of it to be precise. Competitors are subjected to obstacles including – ice cold water baths (the Arctic Enema), 10,000 volt electric shocks (the Electric Eel) and fire (the Phoenix). Full details of this devilishly difficult challenge can be found here.
Human beings have been known to survive the Tough Mudder, and when we heard that Avacta employee John Wilkinson was getting ready for his second (is he mad?!) appearance – to raise money for Peter Pan Nursery – we thought it was time to ask – is an Affimer really all that tough?
Standard practice when working with purified proteins is to keep them either cold (on ice or in the fridge) or frozen, at -20oC or sometimes- 80oC if it’s for a long period of time. So that’s what we do with Affimer products, and we know that at least some of them can last for months in the fridge. What you don’t do with a purified protein is subject it to cycles of rapid cooling and heating, or prolonged periods of time at elevated temperatures (20oC is considered elevated in this context). If these things are done, local formation of salt crystals that can damage the protein is potentially increased, as is local unfolding events that can cascade into global unfolding, or exposure of hydrophobic patches that make the protein stick irretrievably to the test tube wall. In other words, what you don’t do with a protein is run through 12 miles of mud, ice and flames.
The handover took place on Thursday afternoon, just after 2pm. The Affimer had already been sitting outside of the fridge for a while, it was then placed snuggly into John’s armband. There it stayed, at room temperature (probably 18-25 C in Yorkshire that week), until the morning of August 2nd, race day.
As a returning competitor, not only did John undertake the 21 ‘regular’ obstacles, he also got to do the 4 ‘Legionnaire Only’ challenges. This meant John went through at least 3 mud baths, 3 ice-cold water obstacles, and 2, count ‘em, 2, obstacles with those 10,000 volt electric shocks.
On August 4th, we got our Affimer back. Although John was less than 50% functional on his return to work, how did the Affimer fare? We gave it to our CSO, who ran into the lab – he was physically able to having not competed in the Tough Mudder!
36 hours later we were happy to discover that the Affimer was performing well, showing 60% of the activity of the original sample. Pretty amazing: We knew we’d made Affimer technology to be robust- but we didn’t know they’d be this tough. If only we’d given John an antibody too we would be able to compare how both performed. Hey John – fancy another Tough Mudder?