Electrochemical Sensors: From Working Electrodes to Functionalization and Miniaturized Devices

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
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