Introduction to Biosensors

Introduction to Biosensors

Jeong-Yeol Yoon Introduction to Biosensors From Electric Circuits to Immunosensors

Jeong-Yeol Yoon Department of Agricultural and Biosystems Engineering Department of Biomedical Engineering BIO5 Institute University of Arizona Tucson, Arizona USA ISBN 978-1-4419-6021-4 ISBN 978-1-4419-6022-1 (ebook) DOI 10.1007/978-1-4419-6022-1 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2012945945 # Springer Science+Business Media New York 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Preface The title of this textbook, Biosensors: From Electric Circuits to Immunosensors, implies that we are going to learn both electric circuitry (in relation to conventional sensors such as temperature sensors) and biosensors (such as antibody-based immunosensors). The idea of putting these two topics together into a single book came from my decision to add biosensor topics to the Sensors and Controls class taught at the University of Arizona. At that time, I realized there was no available textbook that equally addressed these two topics. In typical sensor textbooks, biosensor topics are relatively sparse. In biosensor textbooks, fundamental electric circuitry is rarely addressed. More importantly, none of those textbooks address the necessary link between these two topics. After all, most biosensors require electric circuit components. This textbook is designed not only for college undergraduate students but also for the scientists and engineers working in the sensor or biosensor industries as a hands-on guide. Although this book may seem to be a collection of laboratory procedures (and certainly can be used for a college-level laboratory class), its primary aim is to deliver hands-on guidance and visual demonstrations of biosensor applications. Readers can complete virtual experiments by reading the lab procedures and viewing the photographs taken during the lab exercises. They can also carry out their own experiments by purchasing the necessary equipment and supplies. This book takes a step-by-step approach towards the end result of building an antibody-based immunosensor from scratch. Many people have provided invaluable help in creating this textbook. First of all, I wish to express my deepest appreciation to my wife, Dr. Sunhi Choi (also at University of Arizona), for her support and advice throughout the writing of this textbook. I also wish to thank my former graduate student Dr. Lonnie J. Lucas (at Applied Energetics) for all the time he spent with me in shaping the entire book, in providing numerous ideas and suggestions, and in proofreading the entire draft. This collaboration with Lonnie was one of the most pleasant collaborations in my entire life. Specifically, Chap. 9 was written jointly with Lonnie. I also thank the students enrolled in my Sensors and Controls class in Fall 2009, Fall 2010, and Fall 2011 at the University of Arizona, who have provided corrections and constructive v

vi Preface suggestions on the draft lab procedures. The help of my teaching assistants for this class, Zachary S. Dean, C. Christopher Stemple, and Scott V. Angus, is greatly appreciated as well. Specifically, Zach collected many photographs of lab exercises and proofread many parts of the manuscript. Other students and postdocs in my lab have also provided numerous corrections and suggestions. My former and current department heads, Dr. Donald C. Slack and Dr. Mark R. Riley, have also provided support and suggestions for my class. I also thank the late Dr. Kenneth Jordan (University of Arizona), who taught the Sensors and Controls class for many years before me and laid the foundations for the lab procedures described in Chaps. 2 to 6. Finally, support and suggestions from the editorial office at Springer, Alison Waldron and Steven M. Elliot, are greatly appreciated. None of this would have been possible without the contributions of all of my students, coworkers, and collaborators.

About the Author Jeong-Yeol Yoon received his B.S., M.S., and Ph.D. degrees in Chemical Engineering from Yonsei University, Seoul (South Korea) in 1992, 1994, and 1999, respectively, under the guidance of Dr. Woo-Sik Kim, in collaboration with Dr. Jung-Hyun Kim, where he worked primarily on polymer colloids. He received his second Ph.D. degree in Biomedical Engineering from the University of California, Los Angeles in 2004, working on lab-on-a-chip and biomaterials, under the guidance of Dr. Robin L. Garrell. He joined the Agricultural & Biosystems Engineering (ABE) faculty in August 2004 and holds joint appointment in the Department of Biomedical Engineering at the University of Arizona. He is also a faculty member in the Biomedical Engineering Graduate Interdisciplinary Program (BME GIDP), Microbiology Graduate Program, and BIO5 Institute at the University of Arizona. Dr. Yoon is currently an Associate Professor and is directing the Biosensors Lab (http://biosensors.abe.arizona.edu). He is a member of the Institute of Biological Engineering (IBE), American Society of Agricultural and Biological Engineers (ASABE) and SPIE The International Society for Optics and Photonics. He currently serves as Associate Editor and Editorial Board Members for numerous journals, including Transactions of the ASABE, Biological Engineering Transactions, Journal of Biological Engineering, and Resource Magazine. Dr. Yoon has published ~50 articles in peer-reviewed journals. vii

Contents 1 Introduction... 1 1.1 Sensors.......................................... 1 1.2 Transducers.... 2 1.3 Biosensors..... 4 1.4 Bioreceptors... 5 1.5 Transducers for Biosensors....... 11 1.6 Overview of this Textbook..... 12 Bibliography... 14 2 Resistors... 15 2.1 Electric Circuit..... 15 2.2 Current and Voltage.... 15 2.3 Resistance and Ohm s Law...... 17 2.4 Resistors in Series, or Voltage Divider... 18 2.5 Potentiometer, or Pot... 19 2.6 Resistors in Parallel, or Current Divider................... 20 2.7 Laboratory: Resistors..... 22 2.7.1 Reading Resistor Values........................ 22 2.7.2 Breadboards... 24 2.7.3 Connecting to a Power Supply.................... 25 2.7.4 Resistance Measurements... 27 2.7.5 Task 1: Resistors in series... 28 2.7.6 Task 2: Resistors in parallel...................... 30 2.7.7 Task 3: Droop... 31 2.7.8 Potentiometer (Pot)... 33 2.8 Further Study: Thévenin s theorem...................... 35 Bibliography... 37 3 Diodes and Transistors... 39 3.1 Semiconductors....... 39 3.2 Diodes........................................... 40 ix

x Contents 3.3 Zener Diode....................................... 43 3.4 Transistors........................................ 44 3.5 Laboratory: Diodes and Transistors... 49 3.5.1 Operational Amplifier... 49 3.5.2 Task 1: LED... 50 3.5.3 Task 2: Zener Diode... 53 3.5.4 Task 3: Transistor... 55 Bibliography... 57 4 Temperature Sensors... 59 4.1 Thermocouple... 59 4.2 Thermistor........................................ 60 4.3 Diode Temperature Sensor... 62 4.4 Transistor Temperature Sensor...... 64 4.5 Laboratory: Temperature Sensors....................... 65 4.5.1 Task 1: Thermistor... 65 4.5.2 Task 2: Zener Diode Temperature Sensor... 66 4.5.3 Task 3: Transistor Temperature Sensor... 69 Bibliography... 73 5 Wheatstone Bridge... 75 5.1 Wheatstone Bridge.... 75 5.2 Strain Gauge... 77 5.3 Cantilever Biosensor... 78 5.4 Laboratory: Wheatstone Bridge......................... 79 5.4.1 Task 1: Wheatstone Bridge... 79 5.4.2 Task 2: Wheatstone Bridge for a Thermistor.......... 81 5.4.3 Task 3: Wheatstone Bridge for a Strain Gauge...... 84 Bibliography... 85 6 Op-amp... 87 6.1 Op-amp... 87 6.2 Basics of Op-amp......... 89 6.3 Voltage Follower or Buffer Op-amp........ 90 6.4 Non-inverting Op-amp...... 91 6.5 Inverting Op-amp................................... 92 6.6 Summing Op-amp.................................. 93 6.7 Differential Op-amp... 94 6.8 Laboratory: Op-amp...... 95 6.8.1 Task 1: Non-inverting Op-amp Operation........... 95 6.8.2 Task 2: Signal Conditioning for Temperature Sensor... 98 Bibliography... 101

Contents xi 7 Light Sensors... 103 7.1 Light... 103 7.2 Photoresistor.... 104 7.3 Photodiode....................................... 105 7.4 Phototransistor... 108 7.5 Light Emitting Diode... 109 7.6 Laser Diode...... 111 7.7 Laboratory: Photodiode... 113 7.7.1 Task 1: Photoconductive Operation.... 113 7.7.2 Task 2: Photovoltaic Operation... 116 Bibliography... 119 8 Spectrophotometry and Optical Biosensor... 121 8.1 Spectrophotometry................................. 121 8.2 Miniature Spectrophotometer......................... 124 8.3 Optical Glucose Sensor.............................. 126 8.4 Laboratory: Glucose Sensor.......................... 128 8.4.1 Task 1: Glucose Assay Kit with a Spectrophotometer....................... 129 8.4.2 Task 2: Glucose Assay Kit with LED/PD Circuit... 134 8.5 Further Study: Pulse Oximeter... 137 Bibliography... 138 9 Fluorescence and Optical Fiber... 141 9.1 Fluorescence..... 142 9.2 Fluorescent Dyes.... 144 9.3 Optical Fibers... 147 9.4 Laboratory: Optical Fiber Spectrometer.... 150 9.4.1 Reflection Probe...... 151 9.4.2 SpectraSuite Software....................... 152 9.4.3 Task 1: Fluorescent Lamp Measurement... 153 9.4.4 Task 2: Fluorescent Excitation and Emission Measurement... 155 Bibliography... 160 10 Electrochemical Sensors... 161 10.1 Electrolytic and Electrochemical Cells...... 161 10.2 Ion-Selective Electrodes (Potentiometric).... 166 10.3 ph Electrode (Potentiometric)... 167 10.4 Electrochemical Glucose Sensor (Amperometric)..... 168 10.5 Conductometric Biosensors..... 170 10.6 Laboratory: ph Meter and Glucose Meter... 171 10.6.1 Buffer... 171 10.6.2 Task 1: Buffer Preparations and Their ph Measurements...... 172

xii Contents 10.6.3 Task 2: ph Meter Circuit.................... 175 10.6.4 Task 3: Commercial Electrochemical Glucose Sensor..... 178 Bibliography... 180 11 Piezoelectric Sensors... 181 11.1 Piezoelectricity................................... 181 11.2 Pressure Sensors...... 183 11.3 Crystal Oscillators... 184 11.4 Quartz Crystal Microbalance..... 184 11.5 Viscoelasticity Consideration in QCM.................. 187 11.6 Flow-Cell QCM as Biosensor...... 189 11.7 Laboratory: Quartz Crystal Microbalance... 190 11.7.1 Task 1: Quantifying BSA Adsorption on QCM Sensor... 190 Bibliography... 197 12 Immunosensors... 199 12.1 Enzyme-Linked Immunosorbent Assay... 199 12.2 Antibodies...................................... 202 12.3 Antibody Fragments and Aptamers... 203 12.4 Lateral-Flow Assay.... 206 12.5 Optical Immunosensors............................. 207 12.6 Surface Plasmon Resonance Immunosensor... 209 12.7 Electrochemical Immunosensors... 210 12.8 Impedance Immunosensors: Interdigitated Microelectrode Immunosensor........................ 212 12.9 Piezoelectric Immunosensors: QCM Immunosensor... 213 12.10 Immunosensing Kits Versus Handheld Immunosensors... 214 12.11 Laboratory: ELISA kit... 215 12.11.1 Task 1: Insulin ELISA Kit..... 215 12.11.2 Task 2: Insulin ELISA Kit with Optical Fiber Spectrometer...... 217 12.11.3 Task 3: Insulin ELISA Kit with Cell Phone Camera... 219 12.12 Further Study: DNA Sensors......................... 221 Bibliography... 222 13 Lab-on-a-Chip Biosensors... 225 13.1 What Is Lab-on-a-Chip............................. 225 13.2 How to Make an LOC: Photolithography and Soft Lithography... 227 13.3 Early LOC: Capillary Electrophoresis.................. 231 13.4 LOC for Point-of-Care Testing....................... 232 13.5 Use of Optical Fibers in LOC... 235 13.6 Sample/Reagent Introduction...... 236

Contents xiii 13.7 Mixing in LOC......... 238 13.8 LOC with Cell Phone Camera........................ 239 13.9 Other Applications of LOC.......................... 239 13.10 Laboratory: Lab-on-a-Chip................... 240 13.10.1 Task 1: LOC Fabrication.................... 241 13.10.2 Task 2: Mixing Experiment.... 243 13.11 Further Study: Latex Immunoagglutination AssayinLOC... 245 13.12 Further Study: Polymerase Chain Reaction in LOC..... 247 Bibliography... 252 Index... 257