Molecular Sensors and Nanodevices

Principles, Designs and Applications in Biomedical Engineering

John X. J. Zhang, Kazunori Hoshino

• Publisher: Academic Press
• Year: 2018
• Print ISBN: 9780128148624
• eBook ISBN: 9780128148631
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Molecular Sensors and Nanodevices: Principles, Designs and Applications in Biomedical Engineering, Second Edition is designed to be used as a foundational text, aimed at graduates, advanced undergraduates, early-career engineers and clinicians. The book presents the essential principles of molecular sensors, including theories, fabrication techniques and reviews. In addition, important devices and recently, highly-cited research outcomes are also cited. This differentiates the book from other titles on the market whose primary focus is more research-oriented and aimed at more of a niche market.- Covers the fundamental principles of device engineering and molecular sensing, sensor theories and applications in biomedical science and engineering- Introduces nano/micro fabrication techniques, including MEMS, bioMEMS, microTAS and nanomaterials science that are essential in the miniaturization of versatile molecular sensors- Explores applications of nanomaterials and biomaterials, including proteins, DNAs, nanoparticles, quantum dots, nanotubes/wires and graphene in biomedicine

Chapter 1

Introduction to molecular sensors

Abstract

Molecular sensors measure physical, chemical, and biological quantities, such as the concentration of ions or proteins, the existence of toxic molecules, and genetic information from cells down to the molecular scale. While the terms biosensors, chemosensors, and chemical sensors are sometimes used interchangeably, molecular sensors are considered a special class with the sensitivity and specificity at molecular scales. Modern molecular sensors are essential parts of many emerging biomedical devices that play significant roles in areas such as basic scientific research or healthcare.

We start the chapter with the discussions of the molecular sensors definition. We explain the functions and structures of molecular sensors and discuss details of applied areas, including the background and requirements for the application. Molecular sensors employ a variety of capture and recognition mechanisms to capture the molecules. We describe antibodies, DNA, and aptamers, which are key elements for molecular recognition. Sensors convert the capture event into a measurable signal through signal transductions. We overview the transduction mechanisms used in molecular sensors, followed by the discussion on the relationship between the sensitivity, responsivity, and noise. At the end of the chapter, we take a look at nature's natural biosensors by examining the olfactory systems of animals including mammals and insects, followed by an overview of animals used as molecular sensors.

Keywords

Molecular sensors; Biosensors; Physical sensors; Chemical sensors; DNA; Antibodies; Aptamers; Olfactory systems; Sensitivity; Responsivity; Noise

Chapter Outline

• 1.1 Introduction
• 1.2 Principles of Molecular Sensors
  • 1.2.1 Definition of Molecular Sensors
  • 1.2.2 Applications of Molecular Sensors
  • 1.2.3 Model of a Molecular Sensor
  • 1.2.4 Example of Molecular Sensor 1: Immunosensor Based on Field Effect Transistor
  • 1.2.5 Example of Molecular Sensor 2: Animal Olfactory System
• 1.3 Capture and Recognition Elements in Molecular Sensors
  • 1.3.1 Antibody-Antigen Binding
  • 1.3.2 DNA as a Recognition Element
  • 1.3.3 Aptamers
  • 1.3.4 Other Recognition Elements
• 1.4 Transduction Mechanisms
  • 1.4.1 Electrical Transduction
  • 1.4.2 Optical Transduction
  • 1.4.3 Mechanical Transduction
  • 1.4.4 Sensitivity of a Transducer
• 1.5 Performance of Molecular Sensors
• 1.6 Animals as Molecular Sensors
  • 1.6.1 Sensitivity of Animal Olfactory Systems
  • 1.6.2 Applications of Animal Molecular Sensors
  • 1.6.3 Discussion on Animals as Molecular Sensors
• 1.7 Cells as Molecular Sensors
• 1.8 Conclusion
• Problems
• References

1.1 Introduction

Sensors act as interfaces that receive and translate information across physical, chemical, and biological domains. Molecular sensors measure the physical, chemical, and biological quantities, such as concentration of ions or proteins, existence of toxic molecules, and genetic information from cells, with the sensitivity and specificity at molecular scales. The purpose of this book is to provide comprehensive coverage of current and emerging technologies of molecular sensing, explaining the principles of molecular sensor design and assessing the sensor types currently available for different applications. We shall discuss the theories and roles of molecular sensors in light of the development of new materials and fabrication technologies. We also discuss the role of nano/micro-fabrication techniques in designing and creating molecular sensors. The miniaturization of versatile molecular sensors opens up a new range of nanoscale-sensing technology.

Key sensing components and designs of many molecular sensors are based on those found in living organisms. Living organisms have wonderful machinery that contains specialized sensors designed to detect a broad range of molecules, such as toxins and nutrients in the external environment, biomolecular interactions, metabolic activities, glucose level, and hormones for the internal environment. These natural systems are the original form of “molecular sensors,” which combine biomolecular recognition with special forms of reporters so that the presence of guests can be “felt” by the organism. These original molecular sensors are the key biotechnologies that enable life to be sustainable, robust, and adaptive. Some of the sensor technologies currently available may not offer the level of sophistication and form factor easily found in nature, but they are improving rapidly with the convergence of information technology, breakthrough of physical design, and advanced manufacturing. These revolutions have already resulted in a variety of applications. The requirement for molecular sensors in which molecules interact with an analyte to produce a detectable change is becoming ever greater. Molecular sensors have been used in a large variety of applications. Modern molecular sensors are essential parts of many emerging medical diagnostic devices that play significant roles in global health, reducing healthcare costs in developed countries, and providing early response to global threats such as pandemics or bioterrorism.

Prominent areas of molecular sensor research are the detection of biomolecules for disease diagnosis, the detection of volatile components for air pollutant characterization, and the detection of chemical analytes for evaluation of physiological activity. Molecular sensors are used in diagnostics, such as glucose monitoring in diabetes patients, body fluids screening for disease detection, and other physical parameters such as temperature and pressure. They are also used in biomedical R&D in drug discovery and evaluation, and protein engineering. Sensors are used in environmental applications such as water quality detection, air pollution monitoring, detection of pathogens, and gas monitoring. Sensors are also used in food safety, such as the detection of contaminants in drinking water, and detection of allergens, and the determination of drug residues. Recent trends in both scientific research and business dev...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• About the authors
• Preface
• Acknowledgement for the first edition
• Acknowledgement for the second edition
• Chapter 1: Introduction to molecular sensors
• Chapter 2: Fundamentals of nano/microfabrication and scale effect
• Chapter 3: Microfluidics and micro total analytical systems
• Chapter 4: Electrical transducers: Electrochemical sensors and semiconductor molecular sensors
• Chapter 5: Optical transducers: Optical molecular sensing and spectroscopy
• Chapter 6: Mechanical transducers: Cantilevers, acoustic wave sensors, and thermal sensors
• Chapter 7: Nanomaterials for molecular sensing
• Chapter 8: Implantable and wearable sensors
• Appendix A: Commercially available sensors
• Appendix B: Fresnel diffraction and Fraunhofer diffraction
• Appendix C: Coupling between the evanescent wave and the surface plasmon
• Appendix D: Analysis of beam bending
• Index