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

Abstract

The nematode worm Caenorhabditis elegans has been widely used as a model organism in biological studies because of its short and prolific life cycle, relatively simple body structure, significant genetic overlap with human, and facile/inexpensive cultivation. Microinjection, as an established and versatile tool for delivering liquid substances into cellular/organismal objects, plays an important role in C. elegans research. However, the conventional manual procedure of C. elegans microinjection is labor-intensive and time-consuming and thus hinders large-scale C. elegans studies involving microinjection of a large number of C. elegans on a daily basis. In this paper, we report a novel microfluidic device that enables, for the first time, fully automated, high-speed microinjection of C. elegans. The device is automatically regulated by on-chip pneumatic valves and allows rapid loading, immobilization, injection, and downstream sorting of single C. elegans. For demonstration, we performed microinjection experiments on 200 C. elegans worms and demonstrated an average injection speed of 6.6 worm/min (average worm handling time: 9.45 s/ worm) and a success rate of 77.5% (post-sorting success rate: 100%), both much higher than the performance of manual operation (speed: 1 worm/4 min and success rate: 30%). We conducted typical viability tests on the injected C. elegans and confirmed that the automated injection system does not impose significant adverse effect on the physiological condition of the injected C. elegans. We believe that the developed microfluidic device holds great potential to become a useful tool for facilitating high-throughput, large-scale worm biology research. V C 2016 AIP Publishing LLC.

3D Manipulation and Imaging of Plant Cells using Acoustically Activated Microbubbles

“…The in‐plane rotations of individual plant cells are characterized and plotted separately for lily (blue) as well as Arabidopsis (red) pollen grains in Figure . Although in‐plane rotation is less relevant for 3D imaging compared to out‐of‐plane rotation, it is crucial for mechanical interventions, such as microinjection, where the specimen is accessed horizontally inside a lab‐on‐chip device . Figure a,b demonstrates that Arabidopsis pollen grains present a more linear relation between the rotation angle and the time than that of the larger lily pollen grain.…”

“…Although in-plane rotation is less relevant for 3D imaging compared to out-of-plane rotation, it is crucial for mechanical interventions, such as microinjection, where the specimen is accessed horizontally inside a lab-on-chip device. [42] Figure 4a,b demonstrates that Arabidopsis pollen grains present a more linear relation between the rotation angle and the time than that of the larger lily pollen grain. A reason might be the stronger shape anisotropy of the lily pollen grain, leading to a change of the area directly exposed to the strong vortex field near the bubble surface.…”

Advanced Microfluidic Assays for Caenorhabditis elegans

“…The in vivo injection of chemical materials that have significant implications in genetics, drug discovery, and other biological applications is another way to study the mechanisms underlying intercellular communication in C. elegans ( Figure 1H). Using a single needle tip of the micromanipulator, localized chemical stimulation can be delivered to a single intestinal cell of the immobilized worms [123,128].…”

Gene Delivery System Using Droplet Injector and Temperature-Controlled Planarian Holder

“…Different formats of microinjection, including microfluidic chips or glass capillary needles, have been demonstrated to generate liquid droplets that contain biomolecules of interest in a precise manner into individual biological objects for a variety of studies [10][11][12][13][14][15]. For the microinjection in worm biology, a microfluidic device regulated by on-chip pneumatic valves has shown loading, immobilization, injection, and sorting of single Caenorhabditis elegans [15]. Another microfluidic device with an open chamber was developed to immobilize single Inventions 2018, 3, 57 2 of 11 C. elegans through negative pressure with a micropipette used for the microinjection into the worm body [16].…”