Development of ‘smart’ wound dressings for biofilm sensing and control

Chronic wounds affect approximately 2 % of the worldwide population and incur healthcare costs in the billions. Key to their persistence is the formation of microbial biofilms, which are accounted for in nearly 80 % of all non-healing wounds. The smart dressing presented herein aims to detect a range of volatile infection protagonists, with a striking colour change that can be visualised with the naked eye, providing 24/7, non-invasive monitoring of infection development and antimicrobial treatment efficacy. A range of coloured indicator films housing dyes responsive to volatile analytes in the wound headspace were developed and tested against porcine skin inoculated with Pseudomonas aeruginosa. Digital images of the indicator film were captured at regular time intervals and the resulting images were aligned and split into red, green and blue (RGB) colour channels to yield semi-quantitative data. vAPCI-MS was exploited to identify additional volatiles for incorporation into the smart dressing design. A CO₂-sensing film comprising xylenol blue dye underwent a marked colour change from blue to yellow within 12 h of inoculation with PAO1, whilst indicators monitoring uninoculated control skin remained blue (no colour change). In addition, vAPCI-MS identified putrescine as an additional volatile of interest, and responsive indicator films were developed for its detection. The marked colour change exhibited by each indicator film is easily visualised by eye and can be digitally analysed to provide semi-quantitative data. This early warning, point-of-care technology is a promising candidate in combatting biofilm development in wounds.