Electrochemical Sensors: From Working Electrodes to Functionalization and Miniaturized Devices

Description

Electrochemical Sensors: From Working Electrodes to Functionalization and Miniaturized Devices provides an overview of the materials, preparation and fabrication methods for biosensor applications. The book introduces the field of electrochemistry and its fundamentals, also providing a practical overview of working electrodes as key components for the implementation of sensors and assays. Features covered include the prompt transfer of electrons, favorable redox behavior, biocompatibility, and inertness in terms of electrode fouling. Special attention is dedicated to analyzing the various working materials systems for electrodes used in electrochemical cells such as gold, carbon, copper, platinum and metal oxides. This book is suitable for academics and practitioners working in the disciplines of materials science and engineering, analytical chemistry and biomedical engineering. Front Cover Electrochemical Sensors: From Working Electrodes to Functionalization and Miniaturized Devices Copyright Contents Contributors Preface Acknowledgments Chapter 1: Biosensors 1.1. Introduction 1.1.1. Analyte 1.1.2. Biorecognition element (bioreceptor) 1.1.3. Transducer 1.1.4. Electrical signal and display 1.2. Characteristic parameter 1.2.1. Selectivity 1.2.2. Stability 1.2.3. Sensitivity 1.2.4. Response time 1.2.5. Linearity 1.3. Electrode systems 1.3.1. Two electrode systems 1.3.2. Three electrode systems 1.3.2.1. Reference electrodes 1.3.2.2. Counter electrode 1.3.2.3. Working electrode 1.4. Biorecognition elements 1.4.1. Antibody 1.4.2. Enzymes 1.4.3. DNA 1.4.4. Aptamer 1.5. Transducers 1.5.1. Parameters governing the transducers choice 1.5.2. Classification of transducers 1.5.2.1. Electrical transducers Conductometric (impedimetric) transducers Ion-sensitive transducers 1.5.2.2. Optical transducers 1.5.2.3. Piezoelectric (mass-sensitive) transducers Acoustic Microcantilever 1.5.2.4. Calorimetric (thermometric) transducers 1.5.2.5. Electrochemical transducers Amperometric transducers Potentiometric transducers 1.5.3. Principles of transduction 1.6. Types of biosensors 1.6.1. Optical biosensor 1.6.2. Electrochemical biosensor 1.6.3. Mass-sensitive (piezoelectric) biosensor 1.6.4. Calorimetric biosensor 1.7. Future prospects and conclusion References Chapter 2: Electrochemistry-Concepts and methodologies 2.1. Electrochemical cells 2.1.1. Galvanic cells 2.2. The electrochemical processes and equation 2.2.1. Mechanism of charge transfer 2.2.2. Electrochemical methods 2.2.2.1. Potentiometric approaches 2.2.2.2. Potentiometric measurements Potentiometric electrochemical cells 2.3. The Nernst Equation: Activity and potential 2.3.1. Junction potentials 2.3.2. Reference electrodes 2.3.2.1. Standard hydrogen electrode (SHE) 2.3.2.2. Coulometric method 2.3.2.3. Controlled-potential coulometry (CPC) Selecting a constant potential Electrolysis time minimization Electrogravimetry 2.3.2.4. Controlled-current coulometry Maintaining current efficiency Endpoint determination 2.3.3. Voltammetric methods 2.3.3.1. Current in voltammetry The Faradaic current: Mass transport effect The Faradaic current: Electron transfer kinetics 2.4. Conclusion References Chapter 3: Metal-based electrodes 3.1. Background 3.2. Metal-based electrode preparation 3.2.1. Mechanical polishing 3.2.2. Piranha solution 3.3. Platinum-based electrodes 3.3.1. Electrochemical cleaning of platinum 3.4. Gold-based electrodes 3.4.1. Electrochemical cleaning of gold 3.5. Copper-based electrodes 3.5.1. Electrochemical cleaning of copper 3.6. Enzyme immobilization methods 3.7. Irreversible enzyme immobilization methods 3.7.1. Covalent bonds 3.7.2. Entrapment and crosslinking methods 3.8. Reversible immobilization methods 3.8.1. Adsorption (noncovalent interactions) 3.8.2. Formation of disulfide bonds 3.9. Specific study of enzyme immobilization on metal-based electrodes References Chapter 4: Carbon and carbon paste electrodes 4.1. Background 4.1.1. Pyrolytic graphite or highly designed PG 4.1.2. Glassy-carbon (GC) 4.1.3. Diamond doped in boron 4.1.4. Composite C-electrodes 4.1.4.1. Carbon-paste electrodes (CPEs) 4.1.4.2. Screen-printed C-electrodes 4.1.4.3. Pencil-graphite sensors 4.1.5. Carbon nanomaterials 4.1.5.1. Graphene and graphene oxide 4.1.5.2. Carbon nano-tubes 4.1.5.3. Fullerene 4.1.5.4. Carbon-dots 4.1.5.5. Graphene quantum-dots(GQDs) 4.1.5.6. Nano-diamonds 4.1.5.7. Carbon nano-pillow 4.1.5.8. Carbon nanofibers 4.1.5.9. Graphene nanoribbons 4.2. Working of carbon electrodes in biosensor fabrication 4.2.1. Graphene (GR), graphene oxide (GO), and reduced graphene oxide (rGO) for bio-sensors 4.2.2. Carbon nano-fibers for biosensors 4.2.3. Carbon nano-tubes for biosensors 4.3. Cleaning of carbon electrodes 4.3.1. Methods for pre-treatment of carbon-based electrodes 4.3.1.1. Mechanical and solvent cleaning 4.3.1.2. Vacuum heating treatment 4.3.1.3. Laser pre-treatment 4.3.1.4. Microwave plasma pre-treatment 4.3.1.5. Radiofrequency plasma treatment 4.3.1.6. Electrochemical pretreatment 4.3.1.7. Comparability of intervention approaches for the carbon-based electrodes 4.3.2. Components impacting electrochemical pre-treatment of sensor 4.4. Chemical modifications for biomolecules conjugation 4.4.1. The need for surface alteration 4.4.2. Metal and metal-oxide nanomaterials altered electrodes 4.4.2.1. Applications in sensing 4.4.3. Carbon nanomaterial (CNMs)-modified electrodes 4.4.3.1. Applications in sensing 4.5. Recent biosensors based on carbon electrodes 4.5.1. Metal and metal oxide 4.5.2. Core-shell 4.5.3. Quantum-dots 4.5.4. Composites 4.5.4.1. Multimetallic nanocomposites 4.5.4.2. Nanocomposite containing biomolecules 4.5.4.3. Semiconductor material-based nano-composites 4.5.5. Nanowires, nanofibers, and nanosheets (1D) 4.6. Uses of carbon nanomaterials (CNMs) as bio-sensing 4.7. Advantages and disadvantages 4.7.1. Immuno-sensors 4.7.2. Enzyme based sensors 4.7.3. Genosensors 4.7.4. Apta-sensors 4.7.5. Microbial biosensors 4.8. Toxicity of carbon nanomaterials 4.9. Conclusion 4.10. Future perspective References Chapter 5: Mercury 5.1. Background 5.1.1. Working of mercury electrodes in biosensor fabrication 5.1.2. Cleaning of mercury electrodes 5.1.2.1. Modification of mercury electrodes 5.2. Recent biosensors based on mercury electrodes 5.2.1. Working and principle of a biosensor 5.2.2. Advantages and disadvantages of mercury-based biosensors 5.3. Suppliers 5.4. Conclusion Acknowledgment Conflict of interest References Chapter 6: Nanostructured electrodes 6.1. Background 6.2. Working of nanostructured electrodes in biosensor fabrication 6.2.1. Immunosensors 6.2.2. Nucleic acid-based biosensors (aptamers) 6.2.3. Enzyme-based biosensors 6.2.4. Electrochemical sensors 6.3. Cleaning of nanostructured electrodes 6.3.1. Chemical regeneration 6.3.1.1. Acid-base-mediated regeneration 6.3.1.2. Detergent-mediated regeneration 6.3.1.3. Urea-mediated regeneration 6.3.1.4. Glycine-mediated regeneration 6.3.2. Thermal regeneration 6.3.3. Electrochemical regeneration 6.4. Chemical modifications for biomolecule conjugation 6.4.1. Antibody (Ab) conjugation 6.4.2. Enzymatic conjugation 6.4.3. DNA-DNA conjugation 6.4.4. Nanomaterial conjugation 6.5. Recent biosensors on nanostructured electrodes 6.6. Advantages and disadvantages 6.7. Suppliers References Chapter 7: Three-dimensional electrodes 7.1. Background 7.2. Working of 3D electrodes in biosensor fabrication 7.3. Chemical modifications and fabrication strategies 7.4. Three-dimensional graphene composites 7.5. Chemical vapor deposition 7.6. Lithographically defined three-dimensional graphene structures 7.7. Hydrothermal method 7.8. Support-assisted and chemically deposited three-dimensional graphene 7.9. Direct electrochemical methods 7.10. Key features of 3D graphene composites and their application in electrochemical sensing 7.11. Recent biosensors on 3D electrodes: Wearable electrochemical biosensors 7.11.1. Saliva-based sensors 7.11.2. Tear-based sensors 7.11.3. Sweat-based sensors 7.11.4. Fabric/flexible plastic-based devices 7.11.5. Epidermal-based sensors 7.11.6. Recent biosensors on 3D electrodes: Electrochemical paper-based biosensors 7.11.7. Paper-devised fabrication 7.11.8. Screen-printed electrodes 7.11.9. Inkjet-printed electrodes 7.11.10. Origami paper-based biosensors References Chapter 8: Biological recognition elements 8.1. Background 8.2. Biological recognition elements 8.3. Receptors 8.3.1. Enzymes 8.3.1.1. Conjugation of enzymes 8.3.1.2. Sensing mechanism behind enzyme-based biosensors 8.3.1.3. Conjugation of proteins 8.3.2. Antibodies 8.3.2.1. Conjugation of antibodies 8.3.2.2. Methodology for immobilization 8.3.3. Nucleic acid biosensors 8.3.3.1. Aptamers 8.3.3.2. Peptide nucleic acid (PNA) 8.3.3.3. Conjugation of nucleic acid 8.3.4. Molecularly imprinted polymers (MIPs) 8.4. Comparison of different biological recognition elements 8.5. Suppliers References Chapter 9: Miniaturization devices: A nanotechnological approach 9.1. Introduction: A journey from macroscale to microscale miniaturization 9.1.1. The pathway of miniaturization and microfluidics 9.1.2. Microfabrication technology: Effective parameters for prototyping and mass production 9.2. Microfluidics and lab-on-a-chip system: Applications and implications 9.3. The precise micromilling process 9.4. Newer devices: Application and incorporation for diagnosis and detection 9.4.1. ``Organ-on-a-chip´´ or ``human-on-a-chip´´ technologies: Raising mimicking models (2D and 3D) for every organ References Chapter 10: Microfluidics and lab-on-a-chip 10.1. Background 10.2. Microfluidic platforms 10.2.1. The importance of microfluidic platforms 10.2.2. PDMS microfluidic platforms 10.2.3. Thermoplastic-based microfluidic platforms 10.2.4. Paper-based microfluidic platforms 10.3. Design of microfluidic channels 10.4. Fabrication of microfluidic devices 10.4.1. Photolithography 10.4.2. Electron beam lithography 10.4.3. Soft lithography techniques 10.4.3.1. Microcontact printing 10.4.3.2. Injection molding 10.4.3.3. Hot embossing 10.4.4. Fabrication strategies for paper microfluidics 10.4.4.1. Wax dipping 10.4.4.2. Wax printing 10.4.4.3. Screen printing 10.4.4.4. Inkjet printing 10.5. Glass-based microfluidic devices 10.6. Silicon-based microfluidic devices 10.7. Recent microfluidic-based biosensors 10.8. Conclusions References Index Back Cover