Micrometer-thick layers of Pseudomonas aeruginosa 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.

中文翻译：

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光谱选择性中红外激光诱导病原菌灭活

在萤石基质上制备微米厚的铜绿假单胞菌层，并通过聚焦中红外飞秒激光辐射进行扫描，该激光经过光谱调谐以实现拉伸 C-H 振动（3 μm）或拉伸 C = O 的选择性激发, 细菌中酰胺基团的 C-N 振动（6 μm）。与更均匀的 3 μm 激光激发相比，后者选择性激发的杀菌效率增强，这通过对激光处理过的细菌层进行活力测定来证明。6-μm 超短激光脉冲对细菌的灭活归因于细胞膜和细胞内核酸中脂质和蛋白质的解离变性。