Jeffrey Hettinger, Rowan University, Glassboro, NJ
Infections from bacteria are a major medical issue impacting 2.8M patients and resulting in 35,000 deaths annually. Implanted orthopedic device related infections are prevalent. Elective surgeries for joint replacements result in 0.7% to 4.2% infection rates but given the large number of approximately 1M implants annually, this results in more than 24,500 device related infections in the United States. The number of this type of procedure in the United States is expected to increase to 4M by 2030. Infections often require hospitalization, revision surgery, or amputation and can result in sepsis leading to death. Orthopedic trauma cases requiring the use if intramedullary nails result in higher infection rates from approximately 1% for closed fractures up to 30% for open fractures. The development of antibiotic resistant bacteria stemming from misuse of pharmaceutical antibiotics amplifies these issues. Non-pharmaceutical solutions to address the large numbers of infections are needed. Bactericidal elements including copper, silver, zinc and others, have been considered as an alternative to antibiotics. Ions of these elements interact with individual bacteria cells to damage the cell wall changing the cell morphology introducing ruptures and cracks leading to their demise. A single ion-single bacterium interaction leads to the killing of bacteria. This simple notion suggests that the bactericidal ions must outnumber the bacteria cells to be fully effective. In the past, silver has been demonstrated to be effective killing bacteria in the laboratory. However, when implanted, the complex nature of the human chemical system reduces the number of available silver ions, and therefore, the bactericidal effectiveness of the pure silver and silver nanoparticles. An active infection can be thought of as 104 or more colony forming units multiplying exponentially in the so-called “logarithmic” phase. Low solubility elements result in a shortage of bactericidal ions which results in the potential to develop resistant bacteria. We present detailed work on the development of silver oxide coatings using reactive sputtering. These coatings have been demonstrated to be effective as a broad-spectrum bactericidal coating. The presentation will highlight important characteristics and measurements which verify the coating efficacy.