(LR-029) Incorporation of a pH-Sensitive Indicator Into Wound Dressings to Improve the Monitoring of Wound Healing Progression
Thursday, May 16, 2024
7:30 PM – 8:30 PM East Coast USA Time
Introduction: The pH level of a wound, and its exudate, is a significant indicator of a wound’s progression through the healing process. The pH of healthy intact skin is acidic (pH≈4-6), whereas it becomes slightly alkaline (pH≈7.4) from exposure to physiological fluids from the body after skin damage.1,2,3 As the wound heals, the wound pH shifts toward neutral and eventually becomes acidic again.However, proliferating bacteria within the wound could cause the wound pH to rise to >9 due to their alkaline byproducts.2,4 Chronic wounds also tend to exhibit high pH levels (pH≈7.15-8.9), potentially from necrotic tissue leading to tissue hypoxia.3,5
Previously, clinicians measured the pH of wounds with glass pH microelectrodes.These devices are fragile, time consuming, only provide a single-point measurement, and cannot be integrated into a dressing.New solid-state pH sensors have been developed that could be integrated into a dressing, but they are relatively expensive and require additional hardware and/or software to operate.This study explores the use of a pH sensitive pigment/indicator that can be easily and inexpensively integrated into wound dressing materials and allow clinicians to easily monitor the patient’s wound state.
Methods: An anthocyanin-based halochromic compound (ABHC), which changes color based on pH, was incorporated into a medical-grade polyurethane foam material used in wound dressings through a proprietary deposition process.The pH sensitivity of the ABHC treatment was evaluated by exposing samples to physiologically relevant pH levels typically experienced during the wound healing process and measuring the pH-induced color change.
Results: The incorporated ABHC successfully imparted halochromatic properties to the prototype dressings.Exposure to the acidic solutions (pH=4) induced samples to quickly change color to red, while alkaline solutions (pH=10) caused the samples to change to purple-blue.Exposure to a neutral pH buffer didn’t cause a significant color change.The conformability/stiffness wasn’t significantly affected by the treatment process.
Discussion: The ABHC treated dressings provide a means by which clinicians can monitor pH changes across the entire wound and use this additional information to better assess the wound state, evaluate the efficacy of the therapeutic treatment, and potentially reveal the location/severity of bacterial infections and/or necrotic tissue.