Nerve Regeneration in Caenorhabditis elegans After Femtosecond Laser Axotomy

We perform submicrometer-scale surgery with femtosecond lasers to study nerve regeneration in the tiny nematode Caenorhabditis elegans, an invertebrate model organism with only 302 neurons. By cutting nanoscale nerve connections inside the nematode C. elegans , the feedback loops that control backward motion of the worm can be disconnected. This operation stops the whole worm from moving backward while leaving its forward motion intact. The femtosecond laser-based axotomy creates little peripheral damage so that the cut axons can regrow, and the worms recover and move backward again within one day. We conduct several assays to assess target specificity, damage threshold, and the extent of femtosecond laser axotomy. We also study nerve regeneration in touch neurons, and report an interesting type of nerve regeneration that salvages the severed parts of neurons from degeneration. The use of femtosecond laser pulses as a precise surgical tool allowed, for the first time, observation and study of nerve regeneration in C. elegans with a simple nervous system. The ability to perform precise axotomy on such organisms provides tremendous research potential for the rapid screening of drugs and for the discovery of new biomolecules affecting regeneration and development