Applications of femtosecond laser ablation for nanoneurosurgery in C. elegans.

We ablate cellular material with submicrometer resolution using tightly-focused, 2-5 nJ femtosecond laser pulses. Due to the nonlinear absorption of laser light, the disruption occurs within the bulk of the sample without incision. The low energy of the pulses minimizes collateral damage. The technique has broad applicability because any optically resolvable structure within the working distance of a high-NA objective can be disrupted. Current applications of this technique include probing cytoskeletal mechanics, imaging brain tissue, and investigating the neurobiology of the nematode worm C. elegans.

As a demonstration of femtosecond laser ablation in C. elegans, we severed individual dendrites of a thermosensory neuron in the worm without damaging nearby neurons. Quantification of the resulting behavioral deficits identifies the contribution of the dissected structures to normal thermotaxis. A similar dissection of osmosensory dendrites showed a lack of regeneration after surgery, in constrast to a previous report of post-surgery motor axon repair.

Improvements to the technique are aimed at increasing the speed of surgery. The subsequent increase in the number of processed worms or samples will permit the study of subtle behaviors and effects, making the technique useful to an even wider range of researchers.