Sensors Based on Nanostructured Materials (eBook)

Acknowledgments 5
Contents 7
Contributors 9
Introduction 11
1.1 Some Data About Nanotechnology 11
1.2 About This Book 15
Bibliography 17
Carbon Nanotube and Fullerene Sensors 20
2.1 Introduction 20
2.2 Carbon Nanotube Synthesis Techniques 21
2.2.1 Carbon Arc-Discharge Technique 21
2.2.2 Laser-Ablation Technique 22
2.2.3 Chemical Vapor Deposition Technique 23
2.2.4 Purification 23
2.3 Carbon Nanotube and Fullerene Sensors 24
2.3.1 Force Sensors - Pressure and Strain 24
2.3.2 Flow Sensors 27
2.3.3 Temperature Sensors 27
2.3.4 Chemical Sensors 28
2.3.5 Biosensors 31
2.3.6 Radiation Sensors 33
2.4 Conclusions 33
References 34
Non-carbon Nanotubes: Hydrogen Sensors Based on TiO2 38
3.1 Introduction 38
3.2 Fabrication of TiO2 Nanotube Arrays 39
3.3 Sensor Development and Operating Characteristics 42
3.3.1 Sensor Design 42
3.3.2 Operating Features 43
3.3.3 Tunability 43
3.3.4 Cross-Sensitivity 46
3.3.5 Room Temperature Sensing 48
3.4 Applications of Titania Nanotube Hydrogen Sensors 49
3.4.1 Self-Cleaning Sensors 49
3.4.2 Hydrogen Sensing for Biomedical Applications: Transcutaneous Sensors 54
3.4.3 Sensor Networks 57
3.4.3.1 Design of the Sensor Network 58
3.5 Summary 65
References 65
Alternative Nanostructured Sensors: Nanowires, Nanobelts, and Novel Nanostructures 67
4.1 Introduction 67
4.2 Novel Nanostructures 68
4.3 Methods of Synthesis and Fabrication 68
4.3.1 Physical Vapor Deposition 68
4.3.1.1 Laser-Assisted Catalytic Growth 68
4.3.1.2 Thermal Evaporation 70
4.3.1.3 Radiofrequency Magnetron Sputtering 72
4.3.2 Chemical Vapor Deposition 72
4.3.2.1 Thermal Chemical Vapor Deposition 72
4.3.2.2 Metal-Organic Chemical Vapor Deposition (MOCVD) 74
4.3.3 Solution-Based Chemistry 75
4.3.3.1 Hydrothermal Synthesis 75
4.3.3.2 Hydrolysis 76
4.3.3.3 Aqueous Chemical Growth 77
4.3.4 Other Synthesis Techniques 77
4.3.4.1 Electrospinning 77
4.4 Sensing Applications: Biological Sensing and Chemical Sensing 78
4.4.1 Biological Sensing 78
4.4.2 Chemical Sensing 81
References 85
Nanosensors: Controlling Transduction Mechanisms at the Nanoscale Using Metal Oxides and Semiconductors 87
5.1 Introduction 87
5.2 Nanosensors 89
5.3 Nanomaterial Synthesis for Sensing 91
5.4 Nanosensing Mechanism Features 99
5.5 Nanosensors Based on Electrical Interaction Through the Surface 100
5.6 Nanosensors Based on Photon Capture: Photodetection at the Nanoscale 121
5.7 Nanosensors Based on Plasmon Resonance: Influence of the Dielectric Constant Variations at the Nanoscale 126
5.8 Nanosensors Based on Mechanical Resonances: Influence of Small Mass Changes onto Nanostructures 128
5.9 Summary 131
References 131
Quantum Dots for Sensing 138
6.1 Introduction. Quantum Technology and Properties: Quantum Wells, Wires and Dots 138
6.2 Synthesis of Quantum Dots 143
6.2.1 QD Growth onto Semiconductor Wafers 144
6.2.2 Nanocrystal Synthesis 147
6.2.3 Core-Shell Nanocrystal Quantum Dots 149
6.2.4 Functionalization of Nanocrystal Quantum Dots 152
6.3 Sensing Applications 154
6.3.1 Ion Indicators 155
6.3.2 In vitro Biological Applications 159
6.3.2.1 Immunoassays 160
6.3.2.2 DNA Detection 161
6.3.2.3 Cell detection 164
6.3.3 In vivo Biological Applications 170
6.3.3.1 Non-selective Imaging 170
6.3.3.2 Targeted Imaging 174
6.3.3.3 Drawbacks of QD Nanocrystals for Bio-applications 176
6.3.4 Other Applications 177
6.4 Conclusion 180
Bibliography 181
Nanostructured Magnetic Sensors 189
7.1 Introduction: Magnetic Sensors and Nanostructures 189
7.1.3 About Magnetic Nanostructures 190
7.1.3 About Technological Applications of Magnetic Nanostructures 192
7.2 Sensing Elements: Synthesis and Magnetic Characterization 195
7.2.1 Magnetic Nanoparticles: Synthesis 195
7.2.1.1 Chemical Synthesis of Magnetic Nanoparticles 195
7.2.1.2 Synthesis of Hybrid Nanoparticles 197
Organic/Inorganic 198
Inorganic/Inorganic 198
Self-Assembling Supracrystals 200
7.2.2 Magnetic Nanowires and Films: Fabrication Techniques 201
7.2.2.1 Fabrication of Nanowires 201
Lithography Methods 202
Using Templates and Self-Assembly 204
7.2.2.2 Fabrication of Thin Films 206
Physical Vapour Deposition (PVD) 206
Sputtering 207
Evaporation 208
Molecular Beam Epitaxy (MBE) 208
Chemical Vapour Deposition, CVD 208
7.2.3 Characterization of Magnetic Nanostructures 209
7.2.3.1 Structure Characterization 209
X-Ray Diffraction 210
X-Ray Fluorescence 210
X-Ray Absorption Spectroscopy 211
7.2.3.2 Techniques to Determine Magnetic Properties of Nanostructures 211
Hysteresis Properties: Vibrating Sample and SQUID Magnetometers and Kerr Effect 211
Magnetic Imaging 214
Magneto-optical Effects 214
Electron Microscopies 214
Scanning Techniques 216
Magnetic Resonance Imaging 218
Magnetoresistance 219
7.3 Magnetic Sensors and Applications 221
7.3.1 Biological Applications Based on Magnetic Nanoparticles 222
7.3.1.1 Biosensors for Detection and Separation 222
7.3.1.2 Magnetic Nanoparticles as Contrast Agents in MRI Imaging 227
Other Applications 229
7.3.2 Magnetic Nanowires and Sensors for Magnetic Scanning Techniques 229
7.3.2.1 Sensors Based on Nanowires Grown into Ordered Membranes 229
7.3.2.2 Magnetic Sensors Based on Scanning Techniques 232
Magnetic Force and Magnetic Resonance Force Microscopies 232
MicroSQUIDs 235
Hall Probe Microscopy 237
7.3.3 Magnetic Sensors Based on Bidimensional Magnetic Nanostructures 239
7.3.3.1 Magnetic Recording and Related Sensors 240
7.3.3.2 Other Sensors Based on Bidimensional Nanostructures 246
Magnetic Computer Sensors for Biomolecules Studies 246
Sensors Based on Magneto-optical Effects 248
Gas and Humidity Sensors Applications 249
7.4 Final Remarks 249
References 250
Encapsulated Probes 259
8.1 Introduction and Rationale 259
8.2 Brief Overview of Optical Probes 259
8.3 Toxicity of Probe Materials 261
8.4 Immobilization Requirements 262
8.5 Encapsulation Strategies 263
8.6 Progress and Opportunities for Encapsulated Probes 264
8.6.1 Liposomes 264
8.6.2 PEBBLEs (Probes Encapsulated by Biologically Localized Embedding) 265
8.6.3 Polyelectrolyte Multilayers 265
8.6.4 Multilayer Capsules 268
8.6.5 Enzymatic Sensors 270
8.7 Summary and Conclusions 274
References 274
Optical Fiber Sensors Based on Nanostructured Coatings 280
9.1 Introduction 280
9.2 Methods of Fabrication of Nanostructured Films on Optical Fibers: the Layer-by-Layer Technique 281
9.3 Types of Devices and Sensing Mechanisms 284
9.3.1 Interferometric Cavities: NanoFabry-Perots 284
9.3.2 Microgratings 290
9.3.3 Coatings on Conical Surfaces 290
9.3.4 Coatings onto Long-Period Gratings 292
9.3.5 Coatings on Hollow Core Fibers 293
9.4 Sensing Applications 295
9.4.1 Humidity 295
9.4.2 Temperature 297
9.4.3 Gas and Volatile Organic Compounds 298
9.4.4 pH and Chemical Species 299
9.4.5 Biological Recognition 302
9.5 Conclusions 303
References 303
Nanostructured Flexible Materials: Metal Rubbertrade Strain Sensors 307
10.1 Introduction 307
10.2 Molecular-Level Self-Assembly Processing: Long-Range Ordered Langmuir-Blodgett (LB) Films and Self-Assembled Monolayers (SAMs) 307
10.2.1 Surfactants and Floating Monolayers 308
10.2.2 Surface Pressure 309
10.2.3 Monolayer Transfer on Solid Surfaces 310
10.2.4 From LB Films to SAMs 311
10.3 Layer by Layer: Toward Shorter-Range Ordered Structures 312
10.3.1 Electrostatic-Based Self-Assembly 312
10.3.2 Factors Influencing Adsorption and Structure 314
10.3.3 LBL Advantages 315
10.4 Metal Rubbertrade Manufacturing 315
10.5 Metal Rubbertrade Material Properties 316
10.6 Metal Rubbertrade Strain Sensors 318
10.7 Summary 320
References 320
Index 322