UCLA

Bacterial infections are a burden on the healthcare industry. Biofilms play a major role in allowing bacteria to thrive on surfaces and allow infections to persist. Biofilm formation in wounds is a potential cause of chronic infections. Biofilm disruption therefore, is essential for successful bacterial infection management.

This work focuses on the safety and efficacy of using laser-generated shockwaves on Staphylococcus epidermidis (RP62A) biofilms in vitro and presents the design and implementation of a compact scanning system as a portable and practical solution for future clinical applications of this technique in wound care.

The system uses a Q-switched, ND:YAG pulsed laser with an output wavelength of 1.064 µm that ablates thin metallic film (Ti or Al) between constraining layer and substrate to generate an acoustic shockwave. The compressive wave propagates through the layered structures and upon reflection at the interfaces generates a tensile wave which is ultimately responsible for biofilm delamination and dislodging bacteria, thereby making them more susceptible to antibiotic treatment, suggesting a novel treatment option for treating biofilm infected wound infections. Preliminary results find a minimum threshold laser beam of 325 mJ energy with a pulse width of 2-6 nanoseconds onto Ti-coated glass substrate focused over 3 mm is required for delamination of biofilm grown on polystyrene petri dishes.

A survey of current methods for treating infected wounds is made to provide context for using this approach. A description of the laser generated shockwave technology and methods used to characterize the shockwave are also presented. Finally, a low-cost portable 2-D scanning platform is designed, constructed and tested successfully.