Intelligent lab-on-a-chip as a new toolbox for real-time biosensing in ecotoxicology

Huang, Y 2017, Intelligent lab-on-a-chip as a new toolbox for real-time biosensing in ecotoxicology, Doctor of Philosophy (PhD), Applied Sciences, RMIT University.


Document type: Thesis
Collection: Theses

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Title Intelligent lab-on-a-chip as a new toolbox for real-time biosensing in ecotoxicology
Author(s) Huang, Y
Year 2017
Abstract An urgent task for aquatic toxicity testing is to develop rapid, sensitive, and cost-effective bioassays. However, little progress has been made in this direction because the lack of appropriate and user-friendly laboratory automation which strongly limits the throughput of aquatic toxicity testing research. Herein, this thesis presents research towards the goal of developing an automated system for aquatic toxicity biotest by building microfluidic lab-on-a-chip (LOC) devices for performing on-chip behavioural toxicity testing.

The proof-of-concept systems integrated innovative LOC devices with miniaturised video recording instruments for the automated analysis of test specimens’ behaviours. The research involves the design of a series of unique caging chip devices as flow-through systems for water quality bioassays using two types of small model organisms (Artemia and Daphnia). The research focuses on the changes in swimming patterns exhibited by test organisms as a rapid endpoint for aquatic toxicity tests. In contrast with conventional mortality-based toxicity biotests, I performed a fully automated, time-resolved video data analysis to dynamically evaluate toxic effects on selected behavioural parameters. For most of the reference chemicals tested, rapid and reliable behavioural changes were observed even at the beginning of exposure. The research demonstrates that innovative LOC technologies and advanced video analysis systems can be new alternatives for cost-effective and user-friendly aquatic toxicity testing protocols.

This research also presents evidence that lipophilic substrates are greatly depleted in LOC systems because of the large hydrophobic surfaces. The electrostatic interaction between hydrophobic surfaces and toxicants leads to the noncovalent adsorption and rapid reduction of chemicals from the tested media, which can cause significant biases. In applying the sensitive fish embryo toxicity test on the LOC system, I postulate that caution is required when performing toxicity biotestings for organic substrates using LOC systems.

Finally, because of the high controllability of LOC technologies, the last part of the research describes the proof-of-concept development of miniaturised LOC devices for studying the toxin avoidance of small aquatic crustaceans. The study exploits the generation of perfusion-based, fluidically isolated domains via laminar flow with a low Reynolds number. The avoidance patterns of free-swimming small crustacean larvae were analysed rapidly, unambiguously, and easily. This study enables a new method for testing aquatic ecotoxicity and lays a foundation for the next generation of environmental biomonitoring systems.
Degree Doctor of Philosophy (PhD)
Institution RMIT University
School, Department or Centre Applied Sciences
Subjects Interdisciplinary Engineering not elsewhere classified
Environmental Technologies
Microelectromechanical Systems (MEMS)
Keyword(s) Lab-on-a-Chip
Microfluidics
Organism tracking
Toxicity
Ecotoxicology
Behaviour
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Created: Mon, 29 May 2017, 10:19:38 EST by Adam Rivett
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