Wound infections are a major threat to recovery from serious injuries and burns. Yet removing dressings to check can be excruciatingly painful and interfere with healing. By the time an infection has spread enough to be visible, it may be hard to control. The unlikely-sounding solution to these problems could be tiny diamonds embedded in a silk dressing.
Just as our bodies run fevers in response to infection, the temperature around a wound rises as septicemia takes hold. A sufficiently sensitive thermometer could therefore alert nurses to bacterial infections in wounds, and RMIT University's Dr Asma Khalid has an alternative to trying to put a thermometer against the injury.
Suitably doped nanodiamonds have shown themselves to be extremely sensitive temperature probes. When exposed to green-light lasers and microwaves, the tiny crystals glow red above a certain temperature. Khalid has co-authored a paper in ACS Applied Materials and Interfaces demonstrating the potential for these tiny diamonds as heat sensors in wounds.
The diamonds are manufactured to include small amounts of negatively charged nitrogen atoms, which emit red light in response to illumination with green. Their emissions increase as the temperature rises between 25 and 50ºC (77 and 122ºF), which conveniently includes human body temperatures. The response is so finely tuned they can be used as a temperature sensor that's accurate to a fraction of a degree.
The last thing anyone with a serious wound wants is fine abrasive material rubbing against it, so the idea of including hard diamonds sounds alarming. However, Khalid told IFLScience if the diamonds are embedded within the dressing's fibers, they shouldn't move against the wound.
Not every material has the strength required for this, but Khalid told IFLScience, “diamonds are silk's best friend,” although perhaps it would be more accurate to say the reverse. When diamonds are embedded in processed silk, they stay deep enough inside the fibers they can't be felt.
Silk has other advantages as a wound dressing, Khalid added. It allows oxygen to reach the skin and is transparent at the relevant wavelengths, allowing staff to see the diamonds' light, but opaque to white light so everyone is not exposed to the gruesome sight of what is underneath. Moreover, Khalid said in a statement, “we were very excited to find the nanodiamond silk membranes showed an extremely high antibacterial resistance to gram negative bacteria,” potentially preventing many infections in the first place.
Diamonds exemplify expense, but Khalid told IFLScience the artificial diamond powder she used cost a few hundred dollars for 200 milligrams. Even a very large wound would only need a milligram of the material – cheap enough that every foot injury could be fixed with diamonds on the soles of our shoes.