We were unable to reproduce published inactivation results, or show any interaction, between 90 femtosecond (fs) pulses
of 850 nm or 425 nm laser radiation and buffer/water, DNA, protein, M13 bacteriophage or E. coli. Using agarose
electrophoresis and polyacrylamide gel electrophoresis, we examined purified plasmid DNA (pUC19), bovine serum
albumin, and DNA and coat proteins extracted from M13 following exposures to irradiances of up to 120 MW/cm2. We
measured M13 viability using an assay for plaque-forming ability in soft agar after exposure to the same irradiances used
for the protein and DNA experiments. Exposures of up 1 GW/cm2 at 850 nm had no effect on the viability of E. coli as
measured by a colony forming assay in soft agar. Peroxynitrite, known to be toxic, to cause single strand breaks in
DNA, and fragment proteins in vitro gave positive results in all assays.