A low-cost microfluidic platform coupled with light emitting diode for optogenetic analysis of neuronal response in C. elegans

Optogenetic method is widely used for dissecting the neuronal function and connectivity in a specific neural circuit, which can help understanding how the animal process information and generate behavior. The nematode C. elegans has a simple but complete nervous system, making it an attractive model to study the dynamics signals of neural circuits. However, in vivo analysis on neural circuits usually rely on the complex and expensive optical equipment to allow optogenetic stimulating the neuron while recording its activities in such a freely moving animal. Hence, in this paper we reported a portable optofluidic platform that works based on optical fiber illumination and functional imaging for worm optogenetic manipulation. A light beam from LED laser pen crossing the 3D-printed optical fiber channel is used to activate the neurons specific-expressed with light sensitive proteins ChR-2. The imaging light path is perpendicular to the stimulation light, which allows activating neuron precisely and measuring cellular signals simultaneously. By using such an easy-to-assemble device, optical stimulation of the specific neurons and detection of dynamic calcium responses of other neurons could be proceeded simultaneously. Thus, the developed microfluidic platform puts forward a simple, rapid and low-cost strategy for further neural circuits studies.