This SBIR Phase I project aims to identify optimal doses of blue light required to inactivate common clinical pathogens known to cause surgical site infections, and test a prototype antimicrobial light emitting dressing that uses the bactericidal effects of blue light to inactivate surface colonizing bacteria and disinfect surgical sites. The potential outcomes of the proposed activity are the development of a thin reusable blue light-emitting bandage that provides effective post-operative site disinfection, ultimately reducing nosocomial related infections. The proposed activity would further the development of antimicrobial blue light therapy devices, providing novel solutions to surgical site infections, Central Line Bloodstream Associated Infections, and wound infections, because of blue light therapy's proven ability to inactivate a wide range of clinical pathogens regardless of their resistance to antibiotics, ability to improve wound healing, and ability to inactivate bacteria in the biofilm state. The outcomes of this project will aid in providing a cost saving solution to Healthcare Associated Infections by reducing their occurrence, reducing the risks of human error, and improving accountability, quality and workflow. Optimization of blue light therapy is needed for clinical application for killing bacteria on the surface of patient's surgical sites, because of a radiant energy threshold that must be passed to inactivate bacteria. Due to the variation in devices and doses used in previous studies, combined with the clinical need for a device which can be easily incorporated into standard infection prevention protocols, further experimentation is needed with a device designed as a wearable for clinical implementation. Objective 1: Determine optimal light dose (fluence) of blue light (405 nm) required to inactivate common gram positive and gram negative bacteria known to cause SSIs. Using in vitro techniques, determine the total fluence of light and treatment times required to achieve bacterial disinfection of at least a one log reduction in bacteria colony forming units. Objective 2: Optimize device to deliver the effective irradiance while maintaining surface temperature below 43 Degree Celsius for safe use on tissue. The device is to not exceed 43 Degree Celsius on the surface of the device's therapeutic surface while delivering effective irradiance, from Objective 1, for inactivation of bacteria on surfaces. Objective 3: Test the device's infection prevention and tissue response in a SSI porcine model. Evaluate the device in a porcine SSI model with surface-inoculated sutured incisions, made to the depth of the fascia, with optimized light-emitting antimicrobial bandage. Success criteria for bacterial disinfection is at least a 90% reduction of CFU per gram of tissue or a multiparametric and semiquantitative score (0-3 range) no greater than 1, based on standard subjective clinical markers, including fever, erythema, induration, and suppuration.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
