Trapping the nematode on a micro chip for the future of science

Abstract

At the basis of neuroscience is the correlation between behavior and neural signals. This relationship is studied using a variety of techniques, including fluorescent intensity measurements of genetically encoded calcium indicators. The simple structure and conservation of some basic developmental pathways between vertebrates and Caenorhabditis elegans makes it an ideal model for studies employing this technique, but it has been difficult to apply neural stimuli in a controlled way to such a small organism. New microfabrication techniques allow the creation of "worm traps" via a combination of lithography and microfluidic regulation. These micro-scale devices have made possible the immobilization of nematodes in the absence of glue (which could affect the worms' neural activity), in addition to offering more control over the application and removal of stimuli than was possible in previous experimental setups. Chronis et al. link an increase in AVA (a type of motor neurons formed by bilaterally symmetric interneuron pairs) neural activity to the initiation of anterior-traveling body waves, and observed an increase in ASH (a type of sensory neurons responsible for a wide range of avoidance behaviors in response to chemical and physical stimulations) neural activity in response to stimulation by high osmotic strength solutions. The microfabrication developments described can be combined with recent advances in the biological sciences, in particular the developmental embryology, to yield solutions to important problems, such as the detection of low concentration substrates and the analysis of homeostasis and embryonic development.