Microfluidic devices for high-resolution whole brain imaging of Drosophila larvae using light-sheet fluorescence microscopy

Abstract

Improving the understanding of the way neurons interact at the whole-brain level is of great interest to neuroscientists. These “circuit diagrams” of the human brain could revolutionize the way neurological diseases are treated, but before this level of study can be conducted, neuroimaging technology must be improved. Using the model organism Drosophila melanogaster, improvements in spatiotemporal resolution of microscopy techniques are being made. Microfluidic devices have been created to improve the spatial resolution of live neuroimaging in Drosophila 3rd instar larva using confocal microscopy, but the desired high temporal resolution has not yet been demonstrated in a live organism. In this research, the high spatial resolution possible using an immobilization device for live larvae is combined with the high temporal resolution of the light-sheet microscope. A microfluidic device was designed to be compatible with the physical constraints of the light-sheet microscope while simultaneously incorporating a 3D-segmental pinning immobilization channel to ensure minimized motion of the CNS of the larvae. The device achieved single-cell resolution (< 5 μm) of the whole brain of a live, intact larva. Z-stack images and time-series captures demonstrated the capability of the microscope to record volumetric images and high image acquisition rates of the live, intact larval CNS respectively.