Disinfection of surgical materials using photo-activated tolonium chloride

Photo-activated disinfection is a technique which has recently become available for use in disinfection in dentistry. This technique makes use of the dye toluidine blue O coupled to a low powered laser to generate singlet oxygen which kills the bacteria without harming the patient. In this paper trials were performed to try to investigate the possibility of the technique for use in other medical applications, particularly related to implants, and orthopedic fixtures. In the trials, samples of stainless steel and polymethylmethacrylate (PMMA) were exposed to Staphylococcus Aureus and Staphylococcus Epidermis bacteria before being treated with a variety of irradiation exposures. Results found that if laser exposure energy exceeded 4.25 J/cm then a log reduction of 4 times CFU/cm might be expected. Results were similar for both the highly reflective stainless steel and transparent PMMA. Trials were also performed using light emitting diode technology and while these results were less effective, it is felt that the rapid rate of developments in this technology could lead to a cost effective route to rolling photo-activated disinfection out to many more medical applications.