A Compliant Superhydrophobic Antimicrobial Photodynamic Therapy Bandage for the Prevention of Multidrug Resistant Wound Infections

Project Summary The prevention of burn infections by multi-species multi-drug resistant (MDR) bacteria is a daunting challenge to clinicians. Antimicrobial treatment (e.g., minocycline or silver sulfadiazine cream) and either a negative pressure device or gauze with an absorbent layer have been the mainstays. However, evidence that these treatments prevent MDR infections is not conclusive, and bacteria can develop resistance to these treatments. Antimicrobial photodynamic therapy (aPDT) shows promise, but low selectivity in delivery of the photosensitizer (PS) to the wound and the development of bacterial resistance to the PS are problematic. Thus, the field urgently needs further advances in prevention of MDR infections in wounds. We propose an innovative bandage that will prevent MDR infections in burn wounds. We have developed a superhydrophobic-aPDT (SH-aPDT) dressing that delivers airborne singlet oxygen which safely addresses these challenges. The device uses an advanced, micro-textured superhydrophobic coating which minimizes direct contact between the dressing and the wound and yet can deliver the airborne singlet oxygen in a highly controllable fashion. The gaseous singlet oxygen kills both Gram-positive and Gram-negative bacteria without introducing the PS, or any other drug, into the wound. Separating the PS from the wound prevents bacterial species from developing resistance to this treatment. We know from our work with a periodontal rat model, that SH-aPDT kills harmful bacteria and promotes healing without harming mammalian cells. The dressing is porous and flexible, allowing wound fluids to be effectively managed, while easily conforming to the wound surface. A flexible red LED light source can be integrated into the bandage to permit complete patient mobility suitable for extended hospital stays, or field use by combat personnel. The development of a SH-aPDT dressing for the delivery of airborne singlet oxygen would be a major breakthrough for the prevention of burn infections. The objective of this proposal is to optimize the dressing design and validate bandage efficacy using an ex vivo porcine skin burn model as well as a murine Balb/c burn in vivo model.