Watching how worms behave in droplets is the basis for a new assay that could find use in high-throughput drug screening.

Caenorhabditis elegans are small worms that have been widely used as a model organism for fundamental research on neurodegenerative disease and related drug discovery. Now, Bingcheng Lin, Jianhua Qin and colleagues at the Dalian Institute of Chemical Physics, China, have designed an on-chip assay to make studying these creatures cheaper and easier.

Each droplet serves as a microreactor, allowing researchers to study an individual worm's response to chemical cues

The team's microfluidic system works by converting an aqueous suspension of worms into droplets separated by a carrier oil. The dimension of each droplet is a perfect match for the size of a single worm. Lin explains: 'The droplets serve as separate microreactors, in which each individual worm's behaviour in response to chemicals can be characterised in real time.' 

Nikos Chronis, an expert on worm immobilisation on-chip, at the University of Michigan, Ann Arbor, US, is enthusiastic about the work. 'The most exciting part is the system's ability to isolate single worms from a population and transport them individually,' he says. Biologists routinely use worm assays to screen for mutants or to quantify the affect of a chemical on worm behaviour, explains Chronis. Traditional assays often involve distributing the worms on multiwell plates which is often time-consuming and labour intensive. 'The proposed technique has the advantage of being (potentially) high-throughput,' says Chronis. 'It facilitates the application of a chemical or drug - allowing one to record an immediate change in behaviour.'

'We believe this system has the potential to accelerate the current whole animal high-throughput assay and enable novel types of assays,' says Lin. He adds that in the future, he hopes to combine the behavioural analysis of worms with drug screening, making this system a powerful method for high-throughput screening at single animal resolution.

Kathleen Too