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Type: Thesis
Title: A microfluidic sensing system for simultaneous monitoring of extracellular Ca(II) and insulin secretion
Author: Huang, Weikun
Issue Date: 2019
School/Discipline: School of Physical Sciences
Abstract: Extracellular Ca²⁺ ([Ca²⁺]ex) is increasingly recognised as an important messenger for intercellular communications. Recent evidence suggests that [Ca²⁺]ex plays a critical role in mediating the pulsatile insulin secretion from the pancreatic β cells, the impairment of which often represents an early pathological defect in the development of type 2 diabetes mellitus (T2DM). The underlying mechanisms for the latter remain to be elucidated, but are constrained by the lack of sensors suitable for the measurement of [Ca²⁺]ex in the extracellular environment. To enable the investigation on dynamic [Ca²⁺]ex and insulin secretion, two fluorescent indicators, Calcein and Rhodamine-5N (Rhod-5N), were systematically evaluated for measuring [Ca²⁺]ex. Under the optimised conditions, both of the two indicators showed robust fluorescent signals and high selectivity to [Ca²⁺]ex. Compared with previous studies, the fluorescence-based methods established for [Ca²⁺]ex in this thesis are easily accessible and inexpensive. Polydimethylsiloxane (PDMS) chip was then designed, fabricated and characterised to be capable of immobilising the biological tissues and manipulating their extracellular environment. Subsequently, a microfluidic sensing system was developed by integrating the optimised fluorescent indicator, microfluidic chip, laser-induced fluorescence (LIF) detection system and enzyme-linked immunosorbent assay (ELISA). The microfluidic sensing system, for the first time, enabled the simultaneous monitoring of the dynamic [Ca²⁺]ex and insulin concentrations in biological samples. The sensing system presented in this work can be used as a novel tool to gain fundamental insights as to how [Ca²⁺]ex is involved in the regulation of the pulsatile insulin secretion in both health and T2DM. The future work in this area may identify novel therapeutic targets for the prevention and treatment of T2DM.
Advisor: Ebendorff-Heidepriem, Heike
Zhao, Tim (Jiangbo)
Wu, Tongzhi
Dissertation Note: Thesis (MPhil) -- University of Adelaide, School of Physical Sciences, 2019
Keywords: Extracellular Ca(ll)
insulin secretion
microfluidic chip
multiplexed sensor
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
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