(625k) Worm Array Device for Studying Gene Expression Analysis In C. Elegans

Gene expression is a complex process affected by genetic and environmental factors, and it often stochastically fluctuates.  C. elegans has been broadly used for gene-expression analysis because of its transparent tissue, completely sequenced genome, mapped neuron wiring, and the ease of applying genetics.  To dissect complex regulatory mechanisms and to get statistically meaningful data, one needs to image a large number of animals at single-cell resolution.  Conventional experimental methods are usually time-consuming and data may not be reliable because of human intervention. Recent development of microfluidic systems increases the throughput of experiments but it usually requires large off-chip equipment and complications in fabrication.  To overcome these limits, we present here a simple microdevice for imaging C. elegans.  We fabricated the device in polydimethylsiloxane which is easy to make.  This microarray does not include any active component so it is easy to be implanted without any complex off-chip components.  Worms can be loaded by syringe manually and they are passively guided to the imaging channels.  Their loading efficiency was tuned by controlling fluidic resistance with electric circuit model and COMSOL model.  This device is more useful when imaging small size worms like L1 developmental stages.  Current L1 imaging devices are high susceptible to be clogged even after using filters because the small size and number of imaging channels.  However, this array has multiple imaging channels in one device and clogging in one single channel does not fail the entire experiment.  Using the developed microfluidic worm arrays, we can image large number of worms and compare differences gene expression pattern in different developmental stages of worms.