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

Abstract

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 pO 2 change and the change in bandage pO 2 at equilibration (CBP 20 ) were found to be directly related to the metabolic oxygen consumption rate of the tissue in contact. Healthy skin demonstrated an initial pO 2 decrease rate of 6.5 , and a larger CBP 20 of 140 mmHg . The change in the bandage pO 2 before and after equilibration with tissue was found to correlate well with histological evidence of skin inflammation in the animals. Birngruber, G. Apiou-Sbirlea, R. Matyal, T. Huang, R. Chan, S. J. Lin, and C. L. Evans, "Non-invasive transdermal two-dimensional mapping of cutaneous oxygenation with a rapid-drying liquid bandage," Biomed.

Transcutaneous oxygen measurement in humans using a paramagnetic skin adhesive film

“…However, the true pO 2 on the skin surface can only be measured by methods that do not consume oxygen during measurement. 45 Optical methods based on fluorescence-, 7 phosphorescence-, [8][9][10] or luminescence-quenching 11,12 and EPR, 32,46 including SPOT chip, do not use oxygen and hence are capable of reporting true skin pO 2 at ambient or physiological temperatures. For example, an oxygen optode device based on fluorescence lifetime imaging (FLIM), reported an average of ~ 20 mmHg of TcpO 2 in the medial lower leg of human subjects (N = 5) measured by heating the skin to 37°C.…”

A paintable phosphorescent bandage for postoperative tissue oxygen assessment in DIEP flap reconstruction

“…These outliers were often acquired immediately after the application of Tegaderm to the newly reconstructed breast and may arise as a combination of reperfusion during flap uptake and equilibration of the bandage material with the living skin beneath. This equilibration effect has been observed and mathematically modeled in prior preclinical studies (51). This indicates that, while the calibration on ex vivo tissue model does not perfectly mimic each patient's in vivo environmental conditions and oxygen/Tegaderm barrier diffusion kinetics, the general trend still follows that of a standard NIRS oximeter.…”

A CFA-Induced Model of Inflammatory Skin Disease in Miniature Swine

“…In addition, we have demonstrated that CFA is an adequate model to study cutaneous inflammation in large animals. The inflammatory reaction can be adequately assessed not only by histology, but noninvasively by simply measuring the induration of the lesions which can be accurately done when animals are injected subcutaneously [ 23 ]; or by the assessment of oxygen consumption in the lesions as we have previously reported [ 24 ]. Thus, this study provides evidence of the safe use of CFA in a humane manner when properly administered into the SC space.…”