Study On Skin Sterilization Of Carbon Dioxide Dotted Laser

Objective The bactericidal effect of laser is a relatively unexplored region which has many advantages over antibiotics. The efficacy of laser is relatively efficient and economic with little pollution and high safety. It should be noted that laser technology is a physical method which is relatively nonselective in bactericidal spectrum and should not be affected by mutation of bacteria. This research uses carbon dioxide fractional laser (CO2fractional laser) to explore the bactericidal efficacy on skin. The study contains2parts. One is basic experiment demonstrating bacteria-killing ability in vitro. The other is case report of clinical application.Methods (1) Spread the plates using staphylococcus aureus (S. aure) solution and Escherichia Coli (E. coli) solution of3different concentration (109/ml,108/ml,107/ml). Then scan the center of these plates with C02fractional laser of different scanning times (3w for once, twice, three times). The plates as control are not exposed to laser. After thermostatic incubation (37℃) for24hours, compare the bacteria colony number of plates with and without laser exposure and explore the influencing factors of bactericidal efficacy.(2) Scan the skin lesion of patient with C02fractional laser. Extract the bacteria sample of skin surface before and after laser treatment. After thermostatic incubation (37℃) for24hours, compare the bacteria quantity before and after laser exposure.Results (1) The bacteria-killing model is a simple, manageable and repeatable method which can also be used for other kind of laser. The C02fractional laser has a strong bactericidal ability, whose bactericidal efficacy is nearly100for both S. aure and E. coli. The antibacterial effect of laser scanning for twice or three times is better than that for only once (P<0.05) But there is no significant difference between that of scanning for twice and for three times. The bactericidal effect is weaker on S. aure of109/ml than that of107/ml. No difference was shown among E.coli of different concentration. From the third day to seventh day after laser exposure, there is no increase of bacterial colony count anymore. The working temperature of laser measured by infrared laser is between29.4℃to30.7℃and quickly drops to room temperature in seconds.(2) The bacterial quantity of skin ulceration and psoriasis is bigger than that of normal skin. The bacterial quantity decreases greatly after exposure to CO2fractional laser. No bleeding, exudation or ulceration is observed. The whole procedure is well tolerated among subjects.Conclusions This study established an excellent model for studying bactericidal efficacy of laser, which can be used for further research of other types of laser. CO2fractional laser is a most advanced technology combining ultra-pulsed energy, fractional technique and scanning mode. This study strongly proved it has a significant anti-bacterial ability. Laser scanning for twice notably improves the bactericidal effect than for only once. But no further improvement is found with further increase of scanning times. CO2fractional laser can kill bacteria using pulsed energy and keep working temperature low as to avoid skin damage. The case report shows powerful bacteria-killing effect on skin lesion with little side-effect and high safety. This method is well-tolerated by all the subjects.