Microfluidic based differential electrochemical sensors
Author
Akay, Özge
Advisor
Kocabaş, Coşkun
Date
2013Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Lab-on-a-chip systems aim to integrate analytical techniques on a single chip to
achieve high-throughput measurements with little reagent. Microfluidic devices use the
advantage of fluid dynamics in microscale to generate new physical phenomena which
are less familiar in macroscale. Laminar flow is one of these emergent phenomena in
microscale dimensions. Fluids flowing in a microchannel with low Reynolds number
(Re), have small inertial effects which suppress the turbulent mixing. Ability to control
liquids without turbulent mixing provides new tools for integration of analytical
techniques on a single chip. In this work we present a new type of electrochemical
device based on hydrodynamic modulation in a microfluidic channel. The presented
microfluidic device is a kind of hydrodynamic modulation voltammetry (µ-HMV) that
uses a periodic modulation of two laminar streams of buffer and analyte solutions in a
micro channel. The periodic modulation of the laminar flow generates periodic
variation of mass transport to the electrode surface. The generated periodic
electrochemical current is detected by a phase-sensitive detector. The differential
electrochemical sensor eliminates charging and other transient background current and
provides high sensitivity with a detection limit of 10 nM. This technique provides a
convenient hydrodynamic electrochemical detection with a relatively simple and
compact instrument which does not require any moving mechanical parts.