Advanced Microfluidic Assays for Caenorhabditis elegans

Abstract

The in vivo analysis of a model organism, such as the nematode Caenorhabditis elegans, enables fundamental biomedical studies, including development, genetics, and neurobiology. In recent years, microfluidics technology has emerged as an attractive and enabling tool for the study of the multicellular organism. "dvances in the application of microfluidics to C. elegans assays facilitate the manipulation of nematodes in high-throughput format and allow for the precise spatial and temporal control of their environment. In this chapter, we aim to illustrate the current microfluidic approaches for the investigation of behavior and neurobiology in C. elegans and discuss the trends of future development.Keywords: C. elegans, chip-based, manipulation, microfluidics, model organism . IntroductionThe invertebrate Caenorhabditis elegans, Drosophila melanogaster, and the vertebrate zebrafish Danio rerio are the most widely studied multicellular organisms. The in vivo analysis of these model organisms allows the understanding of many complex physiological processes, addressing many of the questions relevant to human biology. The choice of model organism depends on the biological question under investigation. For example, C. elegans is simple enough to be experimentally tractable. It has a short life cycle days at °C and lifespan days at °C , passes through four larva L L stages and an adult stage [ ]. Its small size . mm long and µm wide , transparent body at all life stages, and preferred food source Escherichia coli simplify its maintenance on agar plates or liquid cultures allowing visualization of individual cells and organs in intact animals. C. elegans possesses one of the simplest central nervous systems the adult hermaphrodite has neurons . "ecause it is so well studied, rapid identification of signaling pathways, for instance, in studies of aging, has © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. become possible. "bout % of human disease genes have an orthologue in the genome of C. elegans, including those genes associated with "lzheimer disease, Parkinson's disease, Huntington's disease HD , and many other neurodegenerative disorders [ ]. This astonishing degree of correspondence permits the modeling of human ailments in a simple invertebrate without involving actual human subjects and provides a meaningful insight into the pathogenesis of a complex disease phenotype.Traditionally, behavioral genetics is employed as a prime method for neurobiological studies in C. elegans. It is based on manual worm manipulation on a Petri dish or a multiwell plate, and monitoring the effects on various biological processes, such as growth and fertility, by visual inspection. Refreshment of old buffer solutions by a fresh solution is invasive and causes stress both to the lar...

The egg-counter: a novel microfluidic platform for characterization of Caenorhabditis elegans egg-laying

“…Using a flow-through microfluidic device also enables delivery of a consistent diet and experimental stimuli, while removing animal waste and secretions. 47,48 Additionally, the physical arrangement allows for future addition of off-chip components for modulation of perfusate for temporal presentation of diets and stimuli as has been done for other C. elegans microfluidic devices. 41,42,49–51 …”

“…animal waste and secretions. 47,48 Additionally, the physical arrangement allows for future addition of off-chip components for modulation of perfusate for temporal presentation of diets and stimuli as has been done for other C. elegans microfluidic devices. 41,42,[49][50][51] The Egg-Counter platform C. elegans egg laying is sensitive to the chemical environment, with variables like food concentration, CO 2 level, and osmolarity impacting egg-laying behavior.…”

The Egg-Counter: A novel microfluidic platform for characterization ofCaenorhabditis elegansegg-laying

“…The imaging zone enables eggs laid in all 32 arenas to be observed in one location, greatly increasing the potential throughput over traditional worm-tracker assays. Using a flow-through microfluidic device also enables delivery of a consistent diet and experimental stimuli, while removing animal waste and secretions 47,48 . Additionally, the physical arrangement allows for future addition of off-chip components for modulation of perfusate for temporal presentation of diets and stimuli as has been done for other C. elegans microfluidic devices 32,33,[49][50][51] .…”

Pharmaceutical technologies with potential application to insecticide discovery†

“…Later, a wave passed through the industry from about the 1970s till the early 2010s which emphasized creating massive combinatorial libraries of compounds and expression of single biomolecular targets (thus mode of action usually predetermined), and assaying them in vitro in high‐throughput screens (HTS), and highly automated systems and data collection/analysis. Now in the last decade, there has been a return to different types of ‘phenotype‐based in vivo screening’ such as on zebrafish, 14,15 various mammals, 16 nematodes 17 etc., including in the search for drugs for neurological diseases which are often extremely difficult to model in vitro 18–22 . Thus in a sense in pharma, ‘what is old is new again’, though current iterations of phenotype‐based discovery are dramatically augmented by genome editing and genetic engineering.…”