design of nanostructured micro-cyclic voltammetry arrays for microfluidics-based biosensing by ...

153 Pages·2008·16.15 MB·English

DESIGN OF NANOSTRUCTURED MICRO-CYCLIC VOLTAMMETRY ARRAYS
FOR MICROFLUIDICS-BASED BIOSENSING

BY
NAPAT TRIROJ

B.S., COLUMBIA UNIVERSITY, 2001
M.S., UNIVERSITY OF WASHINGTON, 2003

A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN THE
DIVISION OF ENGINEERING AT BROWN UNIVERSITY

PROVIDENCE, RHODE ISLAND
MAY 2008
© Copyright 2008 by Napat Triroj
This dissertation by Napat Triroj is accepted in its present form
by the Division of Engineering as satisfying
the dissertation requirement for the degree of Doctor of Philosophy.

Date______________ ______________________________________
Professor Roderic Beresford, Advisor

Recommended to the Graduate Council

Date______________ ______________________________________
Professor Jimmy Xu, Reader

Date______________ ______________________________________
Professor Anubhav Tripathi, Reader

Approved by the Graduate Council

Date______________ ______________________________________
Sheila Bonde, Dean of the Graduate School

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VITA

Napat Triroj was born in Bangkok, Thailand on August 28, 1978. She received
her B.S. in Electrical Engineering from Columbia University, New York, NY in 2001.
She received her M.S. in Electrical Engineering from University of Washington, Seattle,
WA in 2003. Subsequently, she moved to Brown University, Providence, RI, where she
has been pursuing her doctoral degree. A list of her scientific publications is given below:

N. Triroj, P. Jaroenapibal, H. Shi, J.I. Yeh and R. Beresford, “Nanoelectrode Array
Technology for Direct Electrochemical Detection of Biomolecules.” (submitted 2008)

N. Triroj, J.H. Kim, H. Mukaibo, A. Jaramillo, C.R. Martin, J. Xu, and R. Beresford,
“Conical Gold Nanotubes as Flow-Through Enzyme Electrodes for Direct
Electrochemical Readout in Microfluidic Networks.” (to be submitted 2008)

N. Triroj, P. Jaroenapibal, H. Shi, J.I. Yeh, and R. Beresford, “Nanoelectrode Cyclic-
Voltammetry Cell Arrays in Microchannels as Miniaturized Biosensing Devices,” Proc.
IEEE 34th Annual Northeast Bioengineering Conference (NEBEC), Providence, April
2008.

N. Triroj, M.A. Lapierre-Devlin, S.O. Kelley, and R. Beresford, “Microfluidic Three-
Electrode Cell Array for Low-Current Electrochemical Detection,” IEEE Sensors
Journal, Vol. 6, No. 6, 1395-1402, Dec. 2006.

D. Gatica-Perez, N. Triroj, J.-M. Odobez, A. Loui, and M.T. Sun, “Assessing Scene
Structuring in Consumer Videos,” in Proceedings of International Conference on Image
and Video Retrieval (CIVR), Dublin, Ireland, Jul. 2004.

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ACKNOWLEDGEMENTS

This thesis is completed because of generous help I received from many people.
First, I would like to give my sincerest gratitude to my advisor, Professor Roderic
Beresford, for his guidance throughout my graduate study. Professor Beresford is one of
the most intelligent people I have known. He is also a great teacher who is always willing
to give hands-on assistance in the lab and explain things clearly to make me become a
better scientist. I consider myself really lucky to have a chance to work with him. I will
never forget his kind support and suggestions that have helped me through difficult times
during the research.
Several parts of this dissertation greatly benefited from the collaborations with
many research groups. I would like to thank Professor Jimmy Xu and his postdocs, Dr.
Jin Ho Kim and Dr. Aijun Yin, for their valuable discussions and providing chemicals,
materials, and tools for the study. Similar gratitude is given to Professor Joanne I. Yeh,
Dr. Haibin Shi, Dr. Shoucheng Du, Professor Shana O. Kelley, Melissa A. Lapierre-
Devlin, Professor Charles R. Martin, and Dr. Hitomi Mukaibo for providing samples
necessary for this research. I also would like to thank Professor Anubhav Tripathi for
making time to serve on my dissertation committee.
I would like to thank all the staff in the Division of Engineering at Brown
University for providing both the technical and administrative assistance. Special thanks
to Dr. William R. Patterson III for his advice on microelectronic fabrication and other
technical problems at various points of my research. Similar thanks to Mr. Michael
Jibitsky for always maintaining the clean room facility, and his help in constructing the
v
heater used in the electron beam evaporation process. I extend my similar appreciation to
Mr. Anthony McCormick for his assistance with the electron microscope and Dr. Eva
Campo at the Penn Regional Nanotechnology Facility for her help with the focused ion
beam microscope. I would like to express special thanks to Miss Sandra Spinacci for her
promptness in ordering supplies for the lab, and for having joyful chats with me on many
occasions.
This research is financially supported by Air Force Office of Scientific Research
(AFOSR).
I would like to express my thanks to Min Jun Kim, NaeJye Hwang, Kristina
Davitt, Qiang Zhang, Keng Gaun Lim, Dapeng Wang, Yipping He, Hongbo Peng, Adam
Lazareck, and Gary Withey for their generous advice especially during my early days at
Brown. I wish to thank my labmate, Wei Guo, for his help and support during critical
times throughout these years. I also would like to thank Hyunjin Kim, Jiayi Zhang,
Yanqiu Li, Laura Mehrmanesh, Sutee Olarnrithinun, Siran Manoleehagul, Teng-Fang
Kuo, and Sunil Mandowara for their friendship and for keeping me company during
many late nights in the clean room.
Last and most importantly, I would like to thank my wonderful family whose love
and affection is the source of inspiration for my studies. I am indebted to my parents,
Bubpa Triroj and Somchai Triroj, for their listening, encouragement, and enduring love.
Special thanks to my little sister, Nisara Triroj, for taking care of me and cooking healthy
meals for me. I am blessed to have a supportive and loving husband, Papot Jaroenapibal,
who has always been by my side throughout it all.
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For Mommy and Papa

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TABLE OF CONTENTS

CHAPTER 1: Introduction 1
1.1 Microfluidics-based electrochemical biosensors 1
1.2 Nanostructured electrodes for biosensing 4
1.3 Direct nanoscale conversion of biomolecular signals into 8
electronic information

1.4 Overview of the thesis 9
CHAPTER 2: Development of nanoelectrodes and lab-on-a-chip 14
systems for biosensing applications

2.1 Fabrication of nanoelectrodes 14
2.2 Biosensor functionalized nanoelectrodes 21
2.3 Microfluidics-based electrochemical biosensing devices 27
CHAPTER 3: Relevant theoretical reviews 42
3.1 Fluid flows in microchannels 42
3.2 Mass transport to the electrode surface 44
3.3 Electrical double layer 45
3.4 Electrochemistry at nanoscale electrodes 47
3.5 Electrochemical methods 49
CHAPTER 4: Microfluidic three-electrode cell array for low-current 55
electrochemical detection

4.1 Introduction 55
4.2 Chip design and fabrication 57
4.3 Electrokinetic properties of the microchannels 64
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4.4 Apparatus for cyclic voltammetry experiments 67
4.5 Electrochemical calibration 69
4.6 Electrocatalytic DNA hybridization detection 79
4.7 Npx biosensor for H O detection 82
2 2
CHAPTER 5: Conical gold nanotubes as flow-through enzyme electrodes 86
for direct electrochemical readout in microfluidic networks

5.1 Introduction 86
5.2 Chip design and fabrication 90
5.3 Fluidic test with membrane integration 96
5.4 Apparatus for cyclic voltammetry measurements 97
5.5 GOx-functionalized electrode arrays 98
5.6 Direct electron transfer of GOx 100
CHAPTER 6: Nanoelectrode array technology for direct electrochemical 107
Detection of biomolecules

6.1 Introduction 107
6.2 Chip design and fabrication 110
6.3 Apparatus for cyclic voltammetry measurements 123
6.4 Electrochemical measurements 124
6.5 Functionalized nanoelectrode array: PSA biosensor 128
CHAPTER 7: Concluding remarks 136
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LIST OF TABLES

4.1 The characteristic parameters of 10 mM K Fe(CN) in 1 M KNO at 76
3 6 3
the microfluidic integrated three-electrode cell.

6.1 Variation in normalized current density (at –0.45 V, 100 mV/s) and 128
E as a function of electrode radius
1/2

x