| Description |
Two microfluidics devices are presented, which are used to further study of the Caenorhabditis elegans worm (C. elegans). The first device is a tool for ranking the muscle force between mutant and wild type strains of worms. The second device is a screening chip, which is designed to decrease the amount of time needed to screen the C. elegans worm, and does not require the use of anesthetics to immobilize them for imaging. The muscle force tool operates by compressing a worm in a microchannel with a flexible Polydimethylsiloxane (PDMS) membrane. The force the membrane exerts on the worm is determined by air pressure controlled using a sensitive regulator. The method mimics the natural environment of the worm, where it must move through soil. Worms are tested by loading them into the chip and air pressure against the membrane is increased in increments until the worm becomes immobilized. To rank strains of worms according to muscle force, the pressures at which the worms become immobilized are compared. The chip operates on the hypothesis that a higher pressure indicates a greater muscle contraction force. The chip was tested using three strains of worms: a wild type and two strains with genetic knockouts of specific ion channels at the neuromuscular junction. Immobilization pressures are given for each strain. The screening chip is designed to be operated on a confocal microscope, and is used for taking high magnification images and videos of the worms. To perform the screening process, the chip separates a single worm form a solution containing many worms using a tapered channel and filter. Second, the worm is immobilized for imaging using a flexible PDMS membrane, which compresses the worm against a cover slip. Third, the worm is transported to one of two holding containers. Worm movement through the device is controlled on screen through a custom computer program. This work discusses the design, fabrication and testing results of the microfluidic chips. |
