AVS 56th International Symposium & Exhibition
    Applied Surface Science Tuesday Sessions
       Session AS-TuP

Paper AS-TuP5
Ultrashort Pulse Laser Ablation as a Tool for the Depth Profiling of Staphylococcus Epidermidis Microbial Biofilms

Tuesday, November 10, 2009, 6:00 pm, Room Hall 3

Session: Applied Surface Science Poster Session
Presenter: S. Milasinovic, University of Illinois at Chicago
Authors: S. Milasinovic, University of Illinois at Chicago
M. Blaze, University of Illinois at Chicago
Y. Liu, University of Illinois at Chicago
Y. Zhao, University of Illinois at Chicago
J. Johnston, University of Illinois at Chicago
R.J. Gordon, University of Illinois at Chicago
L. Hanley, University of Illinois at Chicago
Correspondent: Click to Email
Ultrashort pulse laser irradiation is known to cause minimal laser induced damage when interacting with soft biological materials and might therefore be used for depth profiling in mass spectrometric imaging. This work examines the possibility of using this technique for chemically non-destructive ablation of microbial biofilms. Biofilms of Staphylococcus epidermidis were grown on indium tin oxide coated glass slides. ~100 μm thick biofilms were obtained after 3 day incubation by the drip flow method. These biofilms were then irradiated with 45 fsec pulses of 800 nm radiation from a Ti-Sapphire laser. Effects of varying the laser fluence and numbers of pulses were investigated by focusing the laser beam to a ~200 μm spot diameter. Laser ablated craters were imaged by scanning electron microscopy and two-photon laser scanning microscopy. The ablation threshold was determined to be 0.08 J/cm2. Biofilms were then spiked with Br-tyrosine, which was detected by laser desorption postionization mass spectrometry within the intact biofilms before and after laser ablation. Mass spectra obtained at different locations were compared to determine the extent of chemical damage done by laser irradiation.