Nitric oxide (NO) plays an important role in several biological processes, from biofilm inhibition to controlling inflammation and cancer treatment . However, NO is intrinsically unstable, and interest in stable radicals with analogous behaviour, such as (2,2,6,6tetramethylpiperidin-1-yl)oxyl (TEMPO) has rapidly grown. The TEMPO molecule, as shown in Figure , has been reported as effective in anti-biofouling applications , with its potential for use in chronic wound treatment also highlighted . In high doses, TEMPO is lethal to bacterial cells and bio-films . In low doses, it enters the cell and mimics nitric oxide behaviour as a signalling molecule, including, for instance, causing P. aeruginosa biofilm dispersion by reverting sessile cells to a planktonic state through the overstimulation of twitching motility .