[Preparation of critical point dried specimens of mouse embryos with a laser scalpel]

We investigated the use of a laser scalpel for tissue sparing demonstration of the deep structures of critical point dried specimens. A Nd:YAG-Laser emitted pico-second pulses (wavelength 1064 nm, pulse width 30 ps) at pulse energies varying from 1 microJ to 6 mJ was used. Differences in the effects on sputtered and unsputtered specimens were found. We separate the floor of the mouth and pharyngeal fornix in mouse embryos (10. developmental day). It was concluded the laser scalpel is superior to conventional mechanical dissecting methods when applied to small dried specimens. The advantages and disadvantages of the laser scalpel are discussed.