Non-invasive monitoring of skin inflammation using an oxygen-sensing paint-on bandage.

Inflammation involves a cascade of cellular and molecular mediators that ultimately lead to the infiltration of immune cells into the affected area. This inflammatory process in skin is common to many diseases including acne, infection, and psoriasis, with the presence or absence of immune cells a potential diagnostic marker. Here we show that skin inflammation can be non-invasively measured and mapped using a paint-on oxygen sensing bandage in an in vivo porcine inflammation model. After injection of a known inflammatory agent, the bandage could track the increase, plateau, and decrease in oxygen consumption at the injury site over 7 weeks, as well as discern inflammation resultant from injection at various depths beneath the surface of the skin. Both the initial rate of pO2 change and the change in bandage pO2 at equilibration (CBP20) were found to be directly related to the metabolic oxygen consumption rate of the tissue in contact. Healthy skin demonstrated an initial pO2 decrease rate of 6.5 [Formula: see text], and CBP20 of 84 [Formula: see text]. Inflamed skin had a significantly higher initial consumption rate of 55 [Formula: see text], and a larger CBP20 of 140 [Formula: see text]. The change in the bandage pO2 before and after equilibration with tissue was found to correlate well with histological evidence of skin inflammation in the animals.