Effect of femtosecond laser radiation on mammalian oocytes

Abstract

Nucleolus-like bodies (NLBs) of mammalian oocytes are a convenient object for studying the effects of laser radiation on cellular organelles during laser surgery operations. NLBs in mouse germinal vesicle oocytes (GV oocytes) were subject to nanosurgery by means of tightly focused femtosecond laser pulses at near-infrared wavelength. The damage threshold of the NLB material was one-half orders of magnitude below the threshold for the water breakdown by femtosecond pulses. An incision of NLB material with submicron resolution was obtained at a threshold pulse energy. At the pulse energy one order of magnitude higher than the threshold level, significant deformation and rupture of NLBs were observed. Anisotropic deformations of the NLBs and the dynamics of their relaxation indicate the presence of granular structure in these organelles. Mechanical strain and the formation of cavitation and steam-gas bubbles in the place of impact of laser pulses can be described with the help of a model of the laser breakdown of medium.