title: Laser-generated shockwave for clearing medical device biofilms.
abstract: OBJECTIVE
  This study aimed to evaluate a laser method of biofilm interruption from the surface of various common medical devices and from surgically removed sinus tissue with adherent biofilms in a timely manner.
  
  
  BACKGROUND
  Biofilm has emerged as a new threat not amenable to most antibiotic treatments. Biofilms, as opposed to planktonic bacteria, develop an extracellular polymeric slime matrix to facilitate adherence to host tissue or a prosthetic surface and to form a protective shield. A laser-induced biofilms disruption concept was previously described.
  
  
  METHODS
  Biofilms were grown in the laboratory on metallic and plastic medical device surfaces such as stents. Attempts to remove the biofilms with a laser were undertaken three times for each device. Q-switched Nd:YAG laser-generated shockwaves affecting Pseudomonas aeruginosa biofilms expressing yellow fluorescent protein (YFP) biofilm coating were applied with biologically safe parameters utilizing a fiber delivery system and a special probe. A confocal microscope was used to identify the biofilm structure prior to, during, and after laser application. The amount of biofilm removed from the medical devices in time was measured by quantifying green fluorescence.
  
  
  RESULTS
  The biofilm fluctuated and eventually broke off the surface as shock waves neared the target. The time to remove 97.9 ± 0.4% (mean ± 1SD, n = 3) the biofilm from the surface of a Nitinol (NiTi) stent ranged from 4 to 10 s. The detached biofilm was observed floating in fluid media in various microscopic size particles.
  
  
  CONCLUSIONS
  A new treatment modality using laser-generated shockwaves in the warfare against biofilms growing on surgical devices was demonstrated. Q-switched laser pulses stripped biofilm from the surface it adhered to, changing the bacteria to their planktonic form, making them amenable to conventional treatment. This therapeutic modality appears to be rapid, effective, and safe on metallic and plastic medical device surfaces.
authors.affiliation: Department of Otolaryngology, St. Luke's Roosevelt Hospital, New York, NY 10019, USA. vkizhner@gmail.com
authors.forename: Victor
authors.initials: V
authors.lastname: Kizhner
authors.forename: Yosef P
authors.initials: YP
authors.lastname: Krespi
authors.forename: Luanne
authors.initials: L
authors.lastname: Hall-Stoodley
authors.forename: Paul
authors.initials: P
authors.lastname: Stoodley
mesh_terms: D018441:Biofilms / Q000528:radiation effects*; D003666:Decontamination / Q000379:methods*; D004866:Equipment Contamination / Q000517:prevention & control*; D007834:Lasers; D008670:Metals; D018613:Microscopy, Confocal; D010969:Plastics; D011550:Pseudomonas aeruginosa / Q000528:radiation effects*; D013499:Surface Properties
chemical_list: D008670:Metals; D010969:Plastics