Access Type

Open Access Dissertation

Date of Award

January 2014

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Electrical and Computer Engineering

First Advisor

Mark Ming-Cheng Cheng

Abstract

In recent years, graphene has been found to possess extraordinary electronic, optical, mechanical and electrochemical properties. Graphene is optically transparent and mechanically flexible, and has high electron mobility and conductivity. In this thesis, we propose to investigate graphene's properties in the detection of biomolecules as well as the manipulation of biological samples. Graphene without defects has high charge carrier mobility and surface areas, which is ideal for biosensors. However, literature shows a lot of variations in the measurements using graphene biosensors. In addition, the surface functionalization of graphene in order to enhance the specificity has not been fully investigated yet. We propose to combine e-beam lithography (EBL) and dry etching to generate edge defects for biosensor application. These edge defects not only enhance sensitivity but also control the binding sites for surface functionalization. We also demonstrate, for the first time, a microfluidic device based on electrowetting-on-dielectric (EWOD) using a graphene electrode. Hydrophobic surfaces of graphene facilitate self-assembly of the hydrophobic dielectric layer (Teflon). Using graphene electrode, we are able to achieve robust and reversible changes in contact angle without electrolysis. Graphene enables the manipulation of droplets on flexible and transparent substrates using low-cost PET (polyethylene terephthalate). With its high optical transparency, mechanical flexibility and excellent electrical properties, graphene may be suitable in the manipulation of biological samples and in the detection of biomolecules. The research may be applicable in the development of the next generation point-of-care device.

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