Improved Methods of Microinjection in Caenorhabditis elegans: Automation and Microfluidic Systems

C. elegans has become a versatile model organism because of various advantages, such as being a small-sized non-parasitic worm with a transparent body and a short life cycle, along with the capacity to conduct in vivo live worm imaging, genetic amenability and cost-effective laboratory maintenance. It has also gained popularity because of the mapping of the developmental fate of every single cell and full genome sequencing of the worm. Further, among eukaryotic multi-cellular model organisms, C. elegans has the ability to generate a transgenic line in the shortest possible time compared to most other model organisms, which are being used to perform in vivo studies. Two methods for the transformation of C. elegans are widely used, namely, the microinjection of the transgene into the gonads and the bombardment of the transgene on the worm. The microinjection of C. elegans for the purpose of creating transgenic lines to study the effect of various genetic backgrounds is being carried out in almost every worm-based laboratory throughout the world. However, this technique of microinjection into the worm demands high technical expertise and expensive instruments, while the technique itself is low throughput. Until up to three years ago, the microinjection technique remained more or less same. This review focuses on recent advancements in relation to the microinjection technique, which involves the addition of automation via a computerassisted system and the involvement of biomicrofluidic systems in order to increase the efficiency and rate of microinjection, thereby reducing fatigue experienced by the researcher when developing transgenic lines of C. elegans.