Open wounds are something of a paradox – they need to be checked regularly, yet taking the dressing off too often just increases the risk of infection. That's why a group of Swiss researchers has developed a new "glowing" bandage that lets caregivers monitor the healing progress of wounds, from the outside.

When a wound is healing normally, the pH of its fluids initially rises to 8, before settling down to 5 or 6. Should it become chronic, however, the pH fluctuates between 7 and 8.

The bandage incorporates custom-made molecules composed of benzalkonium chloride and pyranine. These fluoresce when exposed to pH levels of around 7.5 – the chronic wound "sweet spot." In order to see that fluorescence, clinicians just need to shine an ultraviolet light on the dressing. They can then leave the dressing in place if normal healing is indicated.

As a side benefit, the benzalkonium chloride in the bandage is known to kill harmful Staphylococcus aureus bacteria.