automated-multimodal-stimulation-simultaneous-neuronal-recording-from

Automated Multimodal Stimulation and Simultaneous Neuronal Recording from Multiple Small Organisms

Fluorescent genetically encoded calcium indicators have contributed greatly to our understanding of neural dynamics from the level of individual neurons ...

Worcester Polytechnic Institute

UMASS Chan Medical School

We demonstrate diffraction-limited and super-resolution imaging through thick layers (tens-hundreds of microns) of BIO-133, a biocompatible, UV-curable, commercially available polymer with a refractive index (RI) matched to water. We show that cells can be directly grown on BIO-133 substrates without the need for surface passivation and use this capability to perform extended time-lapse volumetric imaging of cellular dynamics 1) at isotropic resolution using dual-view light-sheet microscopy, and 2) at super-resolution using instant structured illumination microscopy. BIO-133 also enables immobilization of 1) Drosophila tissue, allowing us to track membrane puncta in pioneer neurons, and 2) Caenorhabditis elegans, which allows us to image and inspect fine neural structure and to track pan-neuronal calcium activity over hundreds of volumes. Finally, BIO-133 is compatible with other microfluidic materials, enabling optical and chemical perturbation of immobilized samples, as we demonstrate by performing drug and optogenetic stimulation on cells and C. elegans.

A polymer index-matched to water enables diverse applications in fluorescence microscopy.

Microfluidic devices offer several advantages for C. elegans research, particularly for presenting precise physical and chemical environments, immobilizing animals during imaging, quantifying behavior, and automating screens. However, challenges to their widespread adoption in the field include increased complexity over conventional methods, operational problems (such as clogging, leaks, and bubbles), difficulty in obtaining or fabricating devices, and the need to characterize biological results obtained from new assay formats. Here we describe the preparation and operation of simple, reusable microfluidic devices for quantifying behavioral responses to chemical patterns, and single-use devices to arrange animals for time-lapse microscopy and to measure neuronal activity. We focus on details that eliminate or reduce the frustrations commonly experienced by new users of microfluidic devices.

Hamilton White

Department of Biomedical Engineering

Worcester Polytechnic Institute

Automated Multimodal Stimulation and Simultaneous Neuronal Recording from Multiple Small Organisms