Inhibition of bacterial attachment by pulsed Nd:YAG laser irradiations: An in vitro study using marine biofilm‐forming bacterium Pseudoalteromonas carrageenovora

Abstract

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.

In Vitro Laser Ablation of Natural Marine Biofilms

“…Electromagnetic radiations such as UV and laser are known to cause bacterial mortality (1,6,7,16). However, the utility of laser irradiation in abating bacterial attachment and removing biofilm has rarely been studied (10,11). Earlier studies showed a considerable reduction in the viable count of the bacterium Pseudoalteromonas carrageenovora at laser fluence of 0.1 J/cm 2 for short duration (10 min).…”

“…The pulse width and repetition rate of this laser were 5 ns and 10 Hz, respectively. The peak power was 20 MW cm Ϫ2 , and the fluence (intensity of laser irradiation expressed as joules per square centimeter) per pulse tested was 0.1 J cm Ϫ2 (kept the same as in our previous studies) (10)(11)(12)14). Laser irradiation in the green light area was used because its attenuation rate in the water column is low.…”

Laser impact assessment in a biofilm‐forming bacterium Pseudoalteromonas carrageenovora using a flow cytometric system

“…These irradiations have therefore been used to sterilize surgical instruments (Powell and Whisenant, 1991). However, the recent advent of research suggests that laser irradiations by the Nd:YAG laser are effective in considerably reducing the growth of marine biofilm-forming bacteria (Nandakumar et al, 2002b;2002c). The biofilm formation on the temperature-sensitive condenser units in power-producing industries causes serious impediments to their smooth functioning (Shariff and Hassan, 1985).…”

“…The pulsed laser irradiations are reported to be effective to reduce bacterial attachment by killing of fouling barnacle larvae and marine planktonic diatoms (Nandakumar et al, 2002c;2002d;2002e). So far, the laser impact assessment studies on bacteria and biofouling organisms focused on static samples, i.e., irradiation on samples in static condition (Charvalos and Karoutis, 2001;Dobson and Wilson, 1992).…”

Silver Containing Stainless Steel as a New Outlook to Abate Bacterial Adhesion and Microbiologically Influenced Corrosion

“…[9][10][11] Stainless steel is the most widely used material in industries. Stainless steels, inherently do not posses antibacterial property.…”