Nandakumar Kanavillil, Obika Hideki, Shinozaki Tatsuya, Ooie Toshihiko, Utsumi Akihiro, Yano Tetsuo
Marine Eco-materials Research Group, National Institute of Advanced Industrial Science and Technology (AIST), Marine Resources and Environment Research Institute, 2217-14 Hayashi-cho, Takamatsu, Kagawa 761-0395 Japan.
Biotechnol Bioeng. 2002 Dec 5;80(5):552-8. doi: 10.1002/bit.10416.
The effect of low mean power laser irradiations with short pulse duration from an Nd:YAG (neodymium-doped yttrium aluminium garnet) laser on a marine biofilm-forming bacterium, Pseudoalteromonas carrageenovora, was investigated in the laboratory. Laser-irradiated bacteria were tested for their ability to attach on nontoxic titanium nitride (TiN) coupons with nonirradiated bacteria as the reference. Two durations of irradiation were tested, 10 and 15 min. Bacterial attachment was monitored after 20 min, 40 min, and 1 h of irradiation. The average laser fluence used for this study was 0.1 J/cm(2). The area of attachment of the irradiated bacteria was significantly less than the reference for both durations of irradiation. The growth of irradiated bacteria showed a longer lag phase than the nonirradiated sample, mainly due to mortality in the former. The bacterial mortality observed was 23.4 +/- 0.71 and 48.6 +/- 6.5% for 10- and 15-min irradiations, respectively. Thus, the results show that low-power pulsed laser irradiations resulted in a significant bacterial mortality and a reduced bacterial attachment on nontoxic hard surfaces.
