ABSTRACT
We report experimental results on the inactivation of encephalomyocarditis virus, M13 bacteriophage, and Salmonella typhimurium by a visible femtosecond laser. Our results suggest that inactivation of virus and bacterium by a visible femtosecond laser involves completely different mechanisms. Inactivation of viruses by a visible femtosecond laser involves the breaking of hydrogen∕hydrophobic bonds or the separation of the weak protein links in the protein shell of a viral particle. In contrast, inactivation of bacteria is related to the damage of their DNAs due to irradiation of a visible femtosecond laser. Possible mechanisms for the inactivation of viruses and bacteria are discussed.
Subject(s)
Bacteriophage M13/radiation effects , Encephalomyocarditis virus/radiation effects , Lasers, Solid-State/therapeutic use , Salmonella typhimurium/radiation effects , Animals , Cattle , Circular Dichroism , DNA, Viral/radiation effects , Microscopy, Atomic Force , Microscopy, Fluorescence, Multiphoton , Serum Albumin, Bovine/chemistry , Serum Albumin, Bovine/radiation effects , Spectrometry, Fluorescence , Spectrum Analysis, Raman , Virion/radiation effectsABSTRACT
Raman spectroscopy is used to study low-wave-number (=20 cm(-1)) acoustic vibrations of the M13 phage. A well-defined Raman line is observed at around 8.5 cm(-1). The experimental results are compared with theoretical calculations based on an elastic continuum model and appropriate Raman selection rules derived from a bond polarizability model. The observed Raman mode is shown to belong to one of the Raman-active axial modes of the M13 phage protein coat. It is expected that the detection and characterization of this low-frequency vibrational mode can be used for applications in biomedical nanotechnology such as for monitoring the process of virus functionalization and self-assembly.