A high-throughput device for size based separation of C. elegans developmental stages

Abstract

Caenorhabditis elegans is a widely used model organism to study development, aging and behavior. Many of these biological studies require staging a large number of worms to assay a synchronized population of animals. Conventional synchronization techniques such as manual picking, gravity stratification and chemical bleaching are labor-intensive and could perturb animals’ physiology. Thus, there is a need for a simple inexpensive technology to sort a mixed population of worms based on their developmental stages with minimal perturbation. Here we demonstrate a simple but accurate and high-throughput technique to sort based on animal size, which correlates well with developmental stages. The device consists of an array of geometrically optimized pillars that act as a sieve to allow worms of specific sizes to rapidly move through. With optimized chamber heights, pillar spacing and driving pressures, these binary separation devices are capable of independently separating a mixture of worms at two different stages at average efficiency of around 95%, and throughput of hundreds of worms per minute. In addition, when four devices are used sequentially, we demonstrate the ability to stratify a mixture of worms of all developmental stages with >85% overall efficiency.

A microfluidic device for automated, high-speed microinjection of Caenorhabditis elegans

“…The success rate could be further enhanced through (i) addressing the issues of micropipette clogging and pipette-worm body misalignment and (ii) more accurate on-chip size synchronization method of the loaded worms using a microfluidic device integrated with computer vision algorithms for automatic worm sizing. 33,38,56 The current worm injection system is more suitable for drug testing/screening applications (in which drug/chemical solutions need to be injected into the worm body); 20,25 however, it is still challenging for the system to perform microinjection of the worm gonad for creating transgenic C. elegans due to the following reasons. The microfluidic device uses a narrow channel to immobilize a C. elegans worm, and the compressed worm body makes the visual identification of the gonad difficult.…”

“…The pumping rate ranges in 240-280 pumps/min for both groups and is in good agreement with values reported in the previous studies on the wild-type N2 worms. 33 This indicates that the microfluidic device and the automated robotic injection are less likely to induce adverse effects on the physiological condition of the injected C. elegans.…”

“…[29][30][31][32][33][34][35][36][37][38][39][40][41] Several microfluidic devices have been reported for immobilizing worms in enclosed channels; 29,37,39,42 however, they do not allow a micropipette to access the worm body for injection. Two microfluidic devices have been developed to facilitate manual C. elegans microinjection.…”

Microfluidic Platform for Analyzing the Thermotaxis of C. elegans in a Linear Temperature Gradient

“…Thus microfluidic systems are used as a platform for various studies with C. elegans. [20][21][22][23][24][25][26][27][28] McCormick et al demonstrated a microfluidic device for analysis of C. elegans orientation. 29 They designed the device in order to immobilize C. elegans and only allow the movement of the head of C. elegans.…”

An integrated platform enabling optogenetic illumination of Caenorhabditis elegans neurons and muscular force measurement in microstructured environments

“…Recent advances in microfluidics and microsystems [6][7][8][9][10][11][12][13][14] have further facilitated investigation into C. elegans' behavior patterns in response to controlled external stimuli. Enabled by state-of-the-art technologies, a variety of external stimuli has been independently studied as a variable in the worm's environment, including temperature, [15][16][17] chemicals, [18][19][20][21] food-related signals, 22 gas concentration, 23 electric field, 24,25 and physical obstacles.…”