  Infection control remains one of the most challenging tasks in wound care,
due to growing antimicrobial resistance and ineffective infection diagnostic
tools at the point-of-care. To integrate therapeutic wound dressings with wound
monitoring capability at the point-of-care to enable informed clinical
decision-making, we investigate the encapsulation of a halochromic dye, i.e.
bromothymol blue (BTB), onto two commercial dressings, i.e. Aquacel Extra and
Promogran, through a simple drop-casting method. Our concept leverages the
infection-associated rise in wound pH, on the one hand, and BTB's colour change
capability in the pH range of healing (pH: 5-6) and infected wounds (pH > 7),
on the other hand. BTB-encapsulated samples show a prompt colour switch
(yellow/orange --> blue) following 1-hour incubation at pH 8. The effect of
swelling ratio, chemical composition and microstructure is then explored to
draw relationships between colour change capability and dressing dye retention.
