Microfluidic system for Caenorhabditis elegans culture and oxygen consumption rate measurements

Mitochondrial respiration is a key signature for the assessment of mitochondrial functioning and mitochondrial dysfunction is related to many diseases including metabolic syndrome and aging-associated conditions. Here, we present a microfluidic Caenorhabditis elegans culture system with integrated luminescence-based oxygen sensing. The material used for the fabrication of the microfluidic chip is off-stoichiometry dual-cure thiol-ene-epoxy (OSTE+), which is well-suited for reliably recording on-chip oxygen consumption rates (OCR) due to its low gas permeability. With our microfluidic approach, it was possible to confine a single nematode in a culture chamber, starting from the L4 stage and studying it over a time span of up to 6 days. An automated protocol for successive worm feeding and OCR measurements during worm development was applied. We found an increase of OCR values from the L4 larval stage to adulthood, and a continuous decrease as the worm further ages. In addition, we performed a C. elegans metabolic assay in which exposure to the mitochondrial uncoupling agent FCCP increased the OCR by a factor of about two compared to basal respiration rates. Subsequent treatment with sodium azide inhibited completely mitochondrial respiration.