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. 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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 collecti on 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 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. vi Preface 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 Agr icultural & 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 [...]... transducers sense light, which is a wave of photons Like temperature transducers, three major types of semiconductors can be used as light transducers, namely the photoresistor, the photodiode, and the phototransistor The photodiode (PD) is probably the most popular Similar to a diode-type temperature transducer, the current–voltage response from a PD is affected by photons A PD is usually combined with a light... net charge to a region of relative negative charge, which is the opposite of the flow of electrons from a negative to a positive charge To measure current, we need to define a unit for electrical charge A coulomb (C) is used for such a unit, which is equal to the charge of 6.25 Â 1018 electrons or comparable positive charges The current is the rate at which positive J.-Y Yoon, Introduction to Biosensors: ... primarily Ohm’s law The resistor is a cornerstone in understanding Ohm’s law, and also one of the most frequently used components in building circuits A resistor is used to convert electric current into voltage signals The resistor is also the main component in a voltage divider circuit We will cover these two important applications in this laboratory demonstration, using resistors in series and/or parallel... 257 Chapter 1 Introduction 1.1 Sensors As implied in the title of this textbook, Biosensors: From Electric Circuits to Immunosensors, we are going to learn both electric circuitry (in relation to conventional sensors such as temperature sensors) and biosensors (such as antibody-based immunosensors), with equal emphasis on both The overarching aim is to build an antibody-based immunosensor... known as a bioreceptor This bioreceptor is a biological material or a biomimetic, which includes antibodies, enzymes, nucleic acids, viruses, bacteria, tissues, etc A bioreceptor will specifically bind to a target analyte and cause a transducer to generate a voltage signal The binding process between bioreceptors and target biomolecules is highly specific For example, the use of an antibody to Escherichia... compound smaller than a protein molecule 6 1 Introduction Fig 1.8 Enzyme (bottom)— substrate (top) binding Upon binding, the enzyme chemically converts the substrate into a different molecule This enzyme-substrate binding is highly specific to shape, similar to a lock-and-key mechanism (Fig 1.8) In a glucose sensor, an enzyme called glucose oxidase (GOx) is used to capture and detect the glucose molecule... can also be used as an excellent bioreceptor 1.5 Transducers for Biosensors 11 In fact, any group of cells that forms a tissue can also be used as a bioreceptor provided that they can recognize and bind to a target molecule Certain virus particles or bacteria that bind to a specific cells and/or tissues can also be used as good bioreceptors 1.5 Transducers for Biosensors In the previous section, two... An analogto-digital converter (A/D converter) performs this conversion Today, all-in-one type sensors have become very popular They incorporate a transducer, an A/D converter, a microprocessor, and a small liquid crystal display (LCD) panel The signal can also be sent to a computer’s universal serial bus (USB) from an A/D converter J.-Y Yoon, Introduction to Biosensors: From Electric Circuits to Immunosensors,... electrons (R ! 1) The best insulators are glass and rubber among common materials Resistors are the passive devices that resist the current flow, and are typically made out of materials that fall somewhere in between the properties of conductors and insulators Resistors are often connected in series or in parallel, which will be discussed in the next sections 18 2 Resistors 2.4 Resistors in Series, or Voltage... Resistors in series, or voltage divider V1 V2 2.5 Potentiometer, or Pot 19 Equation (2.10) indicates that the total resistance RT is equal to the sum of the two resistors In general, the total resistance of the resistors in series can be expressed as: R T ¼ R1 þ R 2 þ Á Á Á þ Rn (2.11) This particular circuit is also known as a voltage divider, as the voltage at the point in between the two resistors . 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. 103 7.2 Photoresistor . 104 7.3 Photodiode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 7.4 Phototransistor 108 7.5