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Bactericidal action of high‐power Nd:YAG laser light on Escherichia coli in saline suspension
Author(s) -
Ward G.D.,
Watson I.A.,
StewartTull D.E.S.,
Wardlaw A.C.,
Wang R.K.,
Nutley M.A.,
Cooper A.
Publication year - 2000
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2000.01144.x
Subject(s) - laser , escherichia coli , suspension (topology) , cuvette , materials science , differential scanning calorimetry , laser power scaling , chemistry , optics , microbiology and biotechnology , biophysics , analytical chemistry (journal) , chromatography , biology , biochemistry , physics , mathematics , homotopy , pure mathematics , gene , thermodynamics
Infra‐red light (1064 nm) from a high‐power Nd:YAG laser caused more than 90% loss of viability of Escherichia coli during exposures that raised the temperature of PBS suspensions of the bacteria to 50 °C in a thermocouple‐equipped cuvette. In contrast, there was minimal loss of viability after heating the same suspensions to 50 °C in a water‐bath, or in a PCR thermal cycler. The mechanism of laser killing at 50 °C was explored by differential scanning calorimetry, by laser treatment of transparent and turbid bacterial suspensions, and by optical absorbancy studies of E. coli suspensions at 1064 nm. Taken together, the data suggested that the bactericidal action of Nd:YAG laser light at 50 °C was due partly to thermal heating and partly to an additional, as yet undefined, mechanism. Scanning electron microscopy revealed localized areas of surface damage on laser‐exposed E. coli cells.