Spectrally-selective mid-IR laser-induced inactivation of pathogenic bacteria
V. O. Kompanets, Svetlana Shelygina, Э. Р. Толордава, S. I. Kudryashov, И. Н. Сараева, Alexey Rupasov, Olga Baitsaeva, Р. А. Хмельницкий, А. А. Ионин, Yulia Yushina, С. В. Чекалин, M. S. Kovalev
Abstract
bacteria were prepared on fluorite substrates and scanned by focused mid-IR femtosecond laser radiation that was spectrally tuned to achieve the selective excitation of either the stretching C-H vibrations (3 μm), or stretching C = O, C-N vibrations (6 μm) of the amide groups in the bacteria. The enhanced biocidal efficiency of the latter selective excitation, compared to the more uniform 3-μm laser excitation, was demonstrated by performing viability assays of laser-treated bacterial layers. The bacterial inactivation by the 6-μm ultrashort laser pulses is attributed to dissociative denaturation of lipids and proteins in the cell membranes and intra-cell nucleic acids.