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Of the reported ~20,000 skin disease related deaths in 2013, 30% were attributed to cutaneous infections, ulcers, wounds, and burns. Wound healing is currently visually assessed by physicians and commonly requires multiple clinical visits for frequent dressing changes. These are often painful and can further compromise tissue health along with increasing infection risks. Clinical workflows for skin wounds often include oxygenation assessment to help guide the course of treatment. However, the low oxygen perfusion intrinsic to these conditions renders standard-of-care blood oxygen saturation tools inaccurate. Transcutaneous oxygen measurements can overcome this issue, albeit with further complications such as time-consuming bedside calibrations and potentially painful application/removal of electrodes.
We present a ‘SMART’ bandage approach that features clinically-validated oxygen sensing molecules embedded within a hydrogel for direct open wound oxygenation measurements. The hydrogel incorporates a phosphorescent red-emitting oxygen-sensing metalloporphyrin covalently attached to a green fluorescent reference dye. As phosphorescence is quenched via collisional energy exchange with molecular oxygen, phosphorescence intensity and lifetime can be used to quantify oxygenation. The emission is bright enough to be visualized by the naked eye, and its intensity was found to increase 10x in oxygen deprived environments (0 mmHg pO2) compared to room air (160 mmHg pO2). Additionally, the hydrogel is capable of swelling up to 400% of its original size in wound exudate while maintaining skin adhesion properties. Along with minimizing the time and materials required for re-dressing, this novel wound dressing has potential for mediating drug delivery and reducing unnecessary patient discomfort.
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