NanoScience in Biomedicine (eBook)

Preface 5
Table of Contents 8
1 Stem Cells and Nanostructured Materials 20
1.1 Introduction 20
1.2 Interaction of Stem Cells with Nanotopographic Substrates 22
1.2.1 Cell Shape and the Cytoskeleton 23
1.2.2 Morphology, Attachment and Proliferation 24
1.2.2.1 Nanosurfaces 24
1.2.2.2 Nanofibers 25
1.2.3 Differentiation 25
1.2.3.1 Nanosurfaces 25
1.2.3.2 Nanofibers 26
1.2.4 Self-Assembling Peptide Nanofibers 27
1.2.5 Summary 27
1.3 Stem Cell Interactions with Nanoparticles 28
1.3.1 Nanoparticles as Contrast Agents 29
1.3.1.1 Super Paramagnetic Nanoparticles 29
1.3.1.2 Quantum Dots 29
1.3.1.3 Nanoshells 29
1.3.2 Nanoparticles as Vehicles 29
1.3.2.1 Silica Nanoparticles 29
1.3.2.2 Polymer Nanoparticles 30
1.3.3 Effect of Internalized Nanoparticles 30
1.3.3.1 Toxicity 30
1.3.3.2 Differentiation 31
1.3.3.3 Cell Internalization of Nanoparticles and Cell Tracking 31
1. Ex Vivo Stem Cell Tracking 32
2. In Vivo Stem Cell Tracking 32
3. Removal and Digestion of Nanoparticle in In Vivo Tracking 34
4. Possible Problems facing In Vivo MR Tracking 34
1.3.3.4 Gene Therepy 35
1.3.3.5 Cancer Therepy 35
1.3.4 Summary 36
1.4 Conclusions 36
Acknowledgements 37
References 37
2 Biomedical Polymer Nanofibers for Emerging Technology 40
2.1 Introduction 40
2.2 Electrospinning Technology-History, Principle, Parameter 42
2.3 Functionalization of Nanofibers 44
2.3.1 Bulk Modification 44
2.3.2 Surface Modification 46
2.4 Biomedical Applications 48
2.4.1 Tissue-Engineered Scaffolds 48
2.4.1.1 Skin 48
2.4.1.2 Cartilage 49
2.4.1.3 Bone 51
2.4.1.4 Blood Vessel 52
2.4.2 Wound Dressing 54
2.4.3 Biomedical Devices and Implants 55
2.4.4 Drug Delivery System 56
2.4.5 Other Applications 57
2.5 Concluding Remark 58
Acknowledgement 58
References 59
3 Nanoscale Mechanisms for Assembly of Biomaterials 62
3.1 Introduction 62
3.2 Non-Covalent Intermolecular Interaction 64
3.2.1 Electrostatic Interaction 65
3.2.1.1 Ion-Ion Interaction 66
3.2.1.2 Ion-Dipole Interaction 66
3.2.1.3 Ion-Induced Dipole Interaction 67
3.2.1.4 Dipole-Dipole Interaction 67
3.2.1.5 Dipole-Induced Dipole Interaction 68
3.2.1.6 Induced Dipole-Induced Dipole Interaction 68
3.2.2 Hydrogen Bonding 69
3.2.3 Hydrophobic Interactions 69
3.2.4 Non-Covalent Interactions in Biological Systems 70
3.2.5 Summary 71
3.3 Approaches for Bioinspired Nanoscale Assembly of Biomaterials 71
3.3.1 Supramolecular Assembly Based Primarily on Ion-Ion Interactions 72
3.3.2 Assembly of Amphiphilic Biomaterials 74
3.3.3 Biomimetic Supramolecular Assembly Based on Hydrogen Bonding 76
3.3.4 Biomimetic Assembly Based on Affinity-Based Interactions 77
3.3.5 Summary 78
3.4 Development of Biomaterials That Mimic The Natural ECM 78
3.4.1 Introduction 78
3.4.2 Non-Covalent Interactions in Natural Extracellular Matrices 79
3.4.3 Biomaterials That Mimic ECM Structures and Properties 80
3.4.3.1 Non-Covalent Assembly of Structural 3-D Hydrogel Matrices for Cell Culture 81
3.4.3.2 Substrates and Scaffolds That Interact Specifically and Non-Covalently with Cells 82
3.4.3.3 Dynamic Matrices That Dissemble in Response to Cell Activity 84
3.4.3.4 Matrices That Interact with Growth Factors via Non-Covalent Interactions 85
1. Heparin-based sequestering 85
2. Gelatin-based sequestering 87
3. Specific sequestering interactions for growth factor delivery 87
3.5 Concluding remarks 89
Acknowledgements 90
References 90
4 Fabrication and Assembly of Nanomaterials and Nanostructures for Biological Detections 95
4.1 Introduction 95
4.2 Semiconductor Quantum Dots and Metal Nanoparticles 96
4.2.1 Principles of Semiconductor QDs and Metal Nanoparticle Biosensors 96
4.2.2 Fabrication of semiconductor QDs and metal nanoparticles for biosensors 99
4.2.3 Assembly of QD and Metal Nanoparticle Arrays for Biosensor Applications 100
4.3 Field Effect Sensors Based on Nanowires and Nanotubes 101
4.3.1 Detection Principles of 1-D Nanowire and Nanotube-Based Biosensors 101
4.3.2 Fabrication of 1-D Nanowires and Nanotubes 102
4.3.3 Assembly of Ordered Nanowire and Nanotube Arrays 104
4.3.4 Horizontally-Aligned Growth of Single-Walled Nanotubes (SWNTs) on Substrates 105
4.4 Micro-cantilever sensors 108
4.4.1 Detection Principle of Micro-Cantilever Sensors 108
4.4.2 Fabrication of the array of micro-cantilever sensors 109
4.5 Summary 110
References 111
5 Nanostructured Materials Constructed from Polypeptides 115
5.1 Introduction 115
5.2 Amino Acids and Their Derivatives: Building Blocks for Nanostructured Materials 116
5.2.1 Canonical Amino Acids 116
5.2.2 Non-canonical Amino Acids 118
5.2.3 Peptidomimetics and Peptide Derivatives 119
5.3 Secondary, Tertiary, and Quaternary Structures in Nanomaterials 121
5.3.1 ß-Sheet Fibrils 121
5.3.2 a-Helices and Coiled Coils 126
5.4 Materials Properties Arising from Peptide Construction 133
5.4.1 Stimulus-Responsiveness 133
5.4.2 Multifunctionality and Modularity 135
5.5 Technological Applications of Nanoscale Peptide Materials 138
5.5.1 Tissue Engineering and Regenerative Medicine 138
5.5.2 Antimicrobials 140
5.5.3 Controlled Drug Release 140
5.5.4 Nanoscale Electronics 141
5.6 Concluding Remarks 141
References 142
6 Photoluminescent Carbon Nanomaterials: Properties and Potential Applications 147
6.1 Introduction 147
6.2 Photoluminescent Carbon Particles-Carbon Quantum Dots 149
6.3 Photoluminescent Carbon Nanotubes 154
6.3.1 A Consequence of Functionalization 155
6.3.2 Photoluminescence Features and Properties 156
6.3.2.1 Effect of Dispersion 159
6.3.2.2 Effect on Raman 161
6.3.3 Defect-Derived vs Band-Gap Emissions 162
6.4 Dots vs Tubes—Luminescence Polarization 163
6.5 Potential Applications 166
Acknowledgement 169
References 169
7 Microwave-assisted Synthesis and Processing of Biomaterials 173
7.1 Introduction 173
7.2 Synthesis of Hydroxyapatite 175
7.2.1 Synthesis in Aqueous Solution 176
7.2.2 Microwave-Hydrothermal Synthesis 181
7.2.3 Synthesis of HA by the Conversion of Precursor Monetite Prepared in Mixed Solvents 182
7.2.4 Prepration of HA Thin Film 184
7.2.5 Synthesis by Solid State Reaction 185
7.3 Synthesis of ß-Tricalcium Phosphate (ß-Ca3(PO4)2) 185
7.4 Synthesis of Calcium Carbonate (CaCO3) 186
7.5 Synthesis of Composite Biomaterials 190
7.6 Synthesis of Functionally Graded Bioactive Materials 192
7.7 Microwave Sintering of Biomaterials 193
References 195
8 Characterizing Biointerfaces and Biosurfaces in Biomaterials Design 197
8.1 Introduction 197
8.2 Characterization of Biointerfaces 200
8.2.1 Surface and Interface Analysis Using Fourier Transform Infrared Spectroscopy 200
8.2.2 Surface and Interface Analysis Using Atomic Force Microscopy 202
8.2.2.1 Atomic Force Microscopy for Surface Imaging 203
8.2.2.2 Atomic Force Microscopy in Study of Cellular Adhesion 204
8.2.2.3 Evaluating Molecular Mechanics Using AFM 205
8.2.3 X-ray Photoelectron Spectroscopy 206
8.2.4 Contact Angle 207
8.2.5 Time-of-Flight Secondary Ions Mass Spectrometry (ToF-SIMS) 208
8.3 Nano-Structuring Surfaces 209
8.3.1 Nanotopology 210
8.3.2 Nanopatterning Surfaces with Biomolecules 211
8.4 Conclusions 214
References 215
9 Carbon Nanotubes for Electrochemical and Electronic Biosensing Applications 224
9.1 Introduction 224
9.2 Design Principles of CNT-Based Biosensors 225
9.2.1 CNTs as Modifiers of Electrode Surfaces 225
9.2.1.1 Non-Oriented Modification 226
9.2.1.2 Oriented Modification 226
9.2.2 CNT-Based Composite Electrodes 228
9.2.3 Nanoparticles Decorated CNT-Based Electrodes 229
9.2.4 CNTs as Key Sensing Elements 230
9.2.5 CNT-Based Biosensors with Immobilized Biological Molecules 231
9.2.5.1 Direct Adsorption 233
9.2.5.2 Entrapment 234
9.2.5.3 Covalent Attachment 236
9.3 Electrochemical Detection of Biomolecules 237
9.3.1 Assessment Criteria of Sensors 243
9.3.2 Electrochemical Biosensors 243
9.3.2.1 Glucose 243
9.3.2.2 Cholesterol 245
9.3.2.3 Choline 245
9.3.2.4 L-Cysteine 245
9.3.2.5 Cytochrome c 245
9.3.2.6 Dopamine 246
9.3.2.7 Folic acid 246
9.3.2.8 Glutathione 247
9.3.2.9 Indole-3-acetic acid 247
9.3.2.10 Lactate 248
9.3.2.11 Lincomycin 248
9.3.2.12 Morphine 248
9.3.2.13 NADH 248
9.3.2.14 Nitric oxide 249
9.3.2.15 Organophosphate compounds 249
9.3.2.16 Phenolic compounds 250
9.3.2.17 Procaine 250
9.3.2.18 Putrescine 250
9.3.2.19 Theophyllin 251
9.3.2.20 Quercetin 251
9.3.2.21 Rutin 251
9.3.2.22 Thiocholine 251
9.3.2.23 DNA 252
9.3.2.24 Others 254
9.4 Field-Effect Transistors Based on SWNTs 255
9.4.1 Protein Recognition 256
9.4.2 DNA Hybridization 258
9.4.3 Enzymatic Study 259
9.4.4 Protein Adsorption 259
9.4.5 Others 260
9.5 Conclusions and Future Prospects 260
Acknowledgement 261
Reference 261
10 Heparin-Conjugated Nanointerfaces for Biomedical Applications 266
10.1 Introduction 266
10.2 Heparin-Bound Biodegradable Polymers for Biocompatible Interfaces 268
10.2.1 Heparin-Conjugated Polylactide (PLA-Hep) 268
10.2.1.1 Synthesis of PLA-Hep 268
10.2.1.2 Blood Compatibility Test 270
10.2.2 Heparin-Conjugated Star-Shaped PLA (sPLA-Hep) 273
10.2.2.1 Synthesis of sPLA-Hep 273
10.2.2.2 Blood Compatibility Test 275
10.2.2.3 In Vitro Assay for Cell Compatibility 278
1. In vitro Cell culture 278
2. Cell growth assay (Actin staining) 278
10.3 Heparin-Conjugated Polymeric Micelles 279
10.3.1 Synthesis of Tetronic®-PCL-Heparin Conjugate 279
10.3.2 Preparation of bFGF Loaded Polymeric Micelle 281
10.3.3 bFGF Release Study 283
10.3.4 Bioactivity of the Released bFGF 285
10.4 Heparin-Immobilized Small Intestinal Submucosa (SIS) 285
10.4.1 Preparation of Heparin-Immobilized SIS 285
10.4.2 Blood Compatibility Test 286
10.4.3 In Vitro Fibroblast Attachment 287
10.4.4 In Vivo Calcification 288
10.5 Conclusions 289
References 289
11 Inorganic Nanoparticles for Biomedical Applications 291
11.1 Introduction 291
11.2 Unguided Drug Delivery Systems 293
11.2.1 Chemical Synthesis of Ceramic Nanomaterials 294
11.2.2 Functionalization of Ceramic Nanomaterials 295
11.3 Magnetically-Guided Drug Delivery Systems 296
11.3.1 Magnetic Guiding 296
11.3.2 Chemical Synthesis and Properties of Magnetic Nanostructures 296
11.3.3 Functionalization of Magnetic Nanoparticles 298
11.3.4 Biocompatibility of Magnetic Nanoparticles for Drug Delivery 299
11.4 Optically-Triggered Drug Delivery Systems 299
11.4.1 Chemical Synthesis and Properties of NIR-Sensitive Nanoparticles 300
11.4.2 Functionalization of NIR-Sensitive Nanoparticles 301
11.4.3 Biocompatibility of NIR-Sensitive Nanoparticles for Drug Delivery 301
11.5 Summary 303
References 303
12 Nano Metal Particles for Biomedical Applications 309
12.1 NMPs as Contrast Agents for Bioimaging 309
12.2 Fluorescing NMPs 311
12.3 NMPs with High Plamon Field for Fluorescence Manipulation 312
12.3.1 NMPs Used for Fluorescence Quenching 313
12.3.2 NMP for Fluorescence Enhancement in Biosensing 314
1. Metal Type 317
2. Particle Size 318
3. Distance between a Fluorophore and an NMP 318
4. Quantum Yield of Fluorophore 319
12.3.3 NMP for Fluorescence Enhancement in Bioimaging 320
12.4 Magnetic NMPs for Bioseparation 321
12.5 Magnetic NMPs for Biosensing 322
12.6 Magnetic NMPs for Cancer Hyperthermia 324
12.7 Multi-Functional NMPs 327
12.8 Conclusions 329
Acknowledgements 329
References 329
13 Micro- and Nanoscale Technologies in High- Throughput Biomedical Experimentation 333
13.1 Introduction 334
13.2 Microarray Technologies 335
13.2.1 Evolution of Microarrays 336
13.2.2 Microarray Fabrication and Applications 337
13.2.3 DNA and cDNA Microarrays 340
13.2.4 Protein and Antibody-Based Microarrays 342
13.2.5 Cell-Based Microarrays 344
13.2.6 Other Microarrays and Microarray-Based Diagnostics 345
13.3 Micro- and Nanoengineering for Biomedical Experimentation 346
13.4 Microfluidics 348
13.5 Other Micro- and Nanoscale Technologies for Biological and Chemical Detection 352
13.6 Conclusions 355
Acknowledgements 355
References 356
14 Delivery System of Bioactive Molecules for Regenerative Medicine 366
14.1 Introduction 366
14.2 Delivery Systems of Bioactive Molecules 367
14.2.1 Importance of Bioactive Molecules Release System for the Regenerative Medicine 367
14.2.2 Scaffold System 372
14.2.3 Injectable Hydrogel System 375
14.2.4 Microspheres System 376
14.2.5 Nanofiber Scaffold System 377
14.3 Differentiation of Adult Stem Cells Using Delivery System of Bioactive Molecules 378
14.3.1 Osteoegensis of MSC 378
14.3.2 Chondrogenesis of MSCs 379
14.4 Repair of Diaphyseal Long Bone Defect with Calcitriol Released Delivery Vehicle and MSCs 380
14.5 Future Directions 383
14.6 Conclusion 384
Acknowledgements 384
References 384
15 Modification of Nano-sized Materials for Drug Delivery 388
15.1 Introduction 388
15.2 Available Methods to Modify Nano-Sized Materials for Drug Delivery 390
15.2.1 Surface Modification 390
15.2.1.1 Physical Modification 390
15.2.1.2 Chemical Modification 391
1. Carbodiimide and Glutaraaldehyde Coupling Chemistry 392
2. PEG Chemistry 392
15.2.1.3 Bio-Specific Modification 393
15.2.2 Shell-Core Modification 393
15.2.3 Bulk Modifications 393
15.3 Applications for Drug Delivery of Modified Nano Sized Biomaterials 394
15.3.1 Long Circulating Delivery 394
15.3.1.1 Stealth Nanoparticles Surface Adsorped Amphipathic Multiblock Copolymers 395
15.3.1.2 Stealth Nanoparticles Surface Chemically Grafting of PEG Chains and Its Derivatives 396
15.3.2 Targeting Delivery 397
15.3.2.1 Brain Targeting and Blood-Brain Barrier 397
1. Coated Nanoparticles 398
2. PEGylated Nanoparticles 399
15.3.2.2 Cell Targeting and Tumor Delivery of Drugs 400
15.3.3 New Therapy and Drug Carriers 401
15.4 Conclusions 403
Acknowledgements 403
References 403
16 Polymeric Nano Micelles as a Drug Carrier 407
16.1 Introduction 407
16.2 Self-Assembly and Micellization of Amphiphilic Block Copolymers 408
16.2.1 Amphiphilic Block Copolymers 408
16.2.2 Micellization of Amphiphilic Block Copolymers 409
16.2.3 Polymeric Micelle Shape 410
16.2.4 Characterization of Polymeric Micelle Size 411
16.2.5 CMC Determination of Polymeric Micelles 412
16.3 Drug Loaded Polymeric Micelles 414
16.3.1 Drug Incorporation in Polymeric Micelles 414
16.3.2 Drug Solubilization Capacity of the Polymeric Micelles 415
16.3.3 Drug Partitioning in Polymeric Micelles 415
16.3.4 Drug Release from Polymeric Micelles 416
16.4 Biological Applications of Polymeric Micelles 417
16.4.1 Biodistribution 417
16.4.2 Accumulation in Target Solid Tumors 418
16.5 Conclusions and Outlook 418
References 419
17 DNA Nanotechnology 424
17.1 Introduction 424
17.2 Basic Features of DNA 425
17.3 Self-Assembly of DNA Aanostructures 426
17.3.1 Basic Concepts 426
17.3.2 Two-Dimensional DNA Array Structures 427
17.3.2.1 DNA Lattice Structures 427
17.3.2.2 DNA Origami Structures 428
17.3.2.3 DNA Nanotube Structures 430
17.3.3 Three-Dimensional DNA Nanostructures 432
17.4 Self-Assembly Properties of DNA Nanostructures 433
17.4.1 DNA Templated Self-Assembly of Biological Molecules 434
17.4.1.1 DNA Cages for Trapping and Crystallization of Biological Molecules 434
17.4.1.2 DNA Scaffolds for Protein Arrays 434
17.4.2 DNA-Templated Self-Assembly of Nanoscale Devices 438
17.5 Application of DNA-Based Nanotechnology 438
17.6 Conclusions and Outlook 442
References 443
18 Nanoscale Bioactive Surfaces and Endosseous Implantology 447
18.1 Introduction 447
18.2 Peri-implant Endosseous Healing and Osseointegration 448
18.2.1 Peri-Implant Endosseous Healing 448
18.2.2 Effect of Implant Surface Characteristics on Osseointegration 450
18.2.3 Potential Advantage of Nanoscale Surfaces 451
18.3 Nanoscale Bioactive Surfaces 453
18.3.1 Nanoscale Textured Surface 453
18.3.2 Nanoscale Biological Molecules 458
18.3.3 Nanoscale Bioactive Calcium Phosphate Coating 459
18.4 Summary 463
Acknowledgements 463
References 463
19 Carbon Nanotube Smart Materials for Biology and Medicine 470
19.1 Introduction 470
19.2 Carbon Nanotube Array Synthesis 472
19.2.1 Array Synthesis 472
19.2.2 Synthesis of Carbon Nanotube Towers 473
19.2.3 CNT Array Nanoskin and Nanostrands 474
19.3 Properties of Carbon Nanotube Arrays 476
19.3.1 Hydrophobic Property 476
19.3.2 Electrowetting Property 477
19.3.3 Capillarity Property 478
19.3.4 Nanotube Array Actuator 479
19.4 Potential Applications of Nanotube Arrays In Biology and Medicine 482
19.4.1 Electronic Biosensors 483
19.4.2 Nanotube Electrodes for Biovoltage and Chemical Sensing 486
19.4.3 Carbon Nanotube Sensor Film for Environmental Monitoring 487
19.4.4 Nanocomposite Materials for Biological Applications 488
19.4.4.1 Tailored Composites Using Carbon Nanotube Thread 489
19.4.4.2 Smart Elastomer 490
19.4.5 In-Body Biosensors: Optimistic Hopes and Wildest Outlook 491
19.4.5.1 Prior Art 492
19.4.5.2 Sensor Initial Design 492
19.4.6 Investigating Neuronal Activity and Function Using Nanotubes 494
19.4.6.1 Goals of Neuron Research 495
19.4.6.2 Synthesis and Fabrication of Carbon Nanotube Array Electrodes 496
19.4.6.3 Culturing Cells on Nanotubes 496
19.4.6.4 Signal Analysis of a Neural Network 497
19.5 Conclusions 499
Acknowledgement 499
References 499
20 Microscopic Modeling of Phonon Modes in Semiconductor Nanocrystals 504
20.1 Introduction 504
20.2 Theory 507
20.2.1 The Valence Force Field Model 507
20.2.2 Application of Group Theory to the Study of Nanocrystals 509
20.2.3 The Bond Charge Approximation 515
20.2.4 Lamb Modes 517
1. Displacements of the Spheroidal l = 0 mode 520
2. Displacements of Torsional l = 1 Modes 520
20.3 Results and Discussion 520
20.3.1 Phonon Density of States for Nanocrystals 520
20.3.2 Raman Intensities 523
20.3.3 Size Effects on the Highest Phonon Frequencies of Si 524
20.3.4 Size Effects on the Lowest Frequencies Phonon for Si 527
20.3.5 Folding of Acoustic Phonons 528
20.3.6 Size Effects on Si Raman Peaks 529
20.3.7 Size Effects on Mode Mixing 530
20.3.8 Size Effects on the Intensities of Ge Raman Peaks 530
20.3.9 Size Effects on the Highest Raman Frequencies for Ge with Fixed or Free Surfaces 532
20.3.10 Existence of Interface Modes for Nanocrystals with Fixed Surfaces 534
20.4 Correspondence between the Microscopic and Macroscopic Active Raman Modes 535
20.4.1 Projection of the Lamb Modes 535
20.4.2 Group Theory Prediction of the Raman Intensities of the Lamb Modes 537
20.4.3 Identifying Lamb Modes within the VFFM-Determined Modes 537
20.4.4 The Radial Distribution Function of Ge Nanocrystals 542
20.4.5 Raman Intensities for Ge NC and Lamb modes 542
20.5 Conclusions 546
Acknowledgements 547
Appendices 547
A.1 The Irreducible Matrices of the Td Group Used in Our Calculations are as Follows 547
A.2 Displacements for the l = 1 Spheroidal Lamb Modes 548
A.3 Displacements for l = 2 Spheroidal Lamb Modes 549
A.4 Displacements for the l = 2 Torsional Lamb Modes 551
A.5 Displacements for the l = 3 Torsional Lamb Modes 552
A.6 Displacements for the l = 4 Torsional Lamb Modes 553
References 554
21 Fracture Processes in Advanced Nanocrystalline and Nanocomposite Materials 556
21.1 Introduction 556
21.2 Specific Structural Features and Plastic Deformation Behavior of Nanomaterials 557
21.3 Brittle and Ductile Fracture Processes in Nanomaterials 562
21.4 Nucleation of Nanocracks at Grain Boundaries and Their Triple Junctions 566
21.5 Intergranular Brittle Fracture Through Nucleation and Convergence of Nanocracks in Nanomaterials 574
21.6 Crack Growth in Nanomaterials. Toughening Mechanisms 577
21.7 Concluding Remarks 582
Acknowledgements 583
References 583
22 Synthesis, Properties and Application of Conducting PPY Nanoparticles 587
22.1 Introduction 588
22.1.1 Synthesis of PPY Nanoparticles 588
22.1.1.1 Microemulsion Polymerization 588
22.1.1.2 Dispersion Polymerization 590
22.1.2 Properties and Application of PPY Nanoparticles 592
22.2 Experimental 599
22.2.1 Materials 599
22.2.2 Polymerization 599
22.2.3 Characterization 599
22.3 Results and Discussion 600
22.3.1 The Effect of Polymerization Temperature on the Yield of the Nanoparticles 600
22.3.2 Size and Its Distribution of the PY/SD Copolymer Nanoparticles 601
22.3.3 Morphology of the PY/SD Copolymer Nanoparticles 602
22.3.4 Mechanism of the Formation and Self-Stabilization of the Nanoparticles 603
22.3.5 Bulk Electrical Conductivity 603
22.4 Conclusions 603
Acknowledgements 604
References 604
23 Field Emission of Carbon Nanotubes 607
23.1 Introduction 607
23.2 Field Emission 608
23.3 Carbon Nanotube Growth Technologies 611
23.4 Characterization of Field Emission From CNTs 618
23.4.1 Effect of Structure on Field Emission 619
23.4.2 Effect of Length and Space 620
23.4.3 Method of field emission enhancement 625
23.4.4 Gated Field-Emission Arrays with Carbon Nanotubes 629
23.5 Summary 633
Acknowledgement 633
References 633
24 Flexible Dye-Sensitized Nano-Porous Films Solar Cells 637
24.1 Introduction 637
24.2 Flexible DSSCs and Low Temperature Preparation 641
24.3 Electron Transport and Back Reaction at the TiO2/ Electrolyte Interface 648
24.3.1 Factors that Determine Efficiency 648
24.3.2 Techniques for Measuring Electron Transport and Back Reaction 650
24.3.3 Results Obtained with Low-Temperature Films 653
24.3.4 Recent Developments and Outlook 657
24.4 Interfacial Electron Transfer, Charge Separation and Recombination 658
24.4.1 Heterogeneous Electron Transfer 660
24.4.2 Charge Separation at the Film/Dye Interface 663
24.4.3 Charge Recombination at the Film/Redox/Dye Interface 664
24.5 Summary 665
References 665
25 Magnetic Nanofluids: Synthesis and Structure 669
25.1 Introduction 670
25.1.1 Ferrofluids—Magnetically Controllable Nanofluids 670
25.1.2 Early History of Magnetic Fluids (A Short Review) 670
25.1.3 Composition, Structure and Macroscopic Behavior 672
25.2 Synthesis of Magnetic Nanofluids 675
25.2.1 Generalities 675
25.2.2 Synthesis of Nanosized Magnetic Particles 675
25.2.2.1 Chemical Co-Precipitation 675
25.2.2.2 Thermal Decomposition. Size Selection Procedures 676
25.2.2.3 Iron and Cobalt Nanoparticles 678
25.2.3 Magnetic Nanofluids with Organic Carriers 680
25.2.3.1 Colloidal Stability, Sterical Stabilization 680
25.2.3.2 Synthesis Procedures 681
25.2.4 Water Based Magnetic Nanofluids 685
25.2.4.1 Stabilization Mechanisms 685
25.2.4.2 Synthesis Procedures, Technical Grade and Biocompatible Water Based MNFs 686
25.2.4.3 Surfactant Layers and Colloidal Stability 689
25.2.5 Long-Term Colloidal Stability of Magnetic Nanofluids 692
25.2.5.1 Effects of Surface Coating and Size of Magnetic Nanoparticles 692
25.2.5.2 Functionalized Coatings 696
25.2.6 Dilution Stability 698
25.3 Structure Investigations 703
25.3.1 Particle Structure 703
25.3.1.1 Non-Polarized Neutrons 703
25.3.1.2 Polarized Neutrons 710
25.3.1.3 Contrast Variation 715
25.3.2 Interaction 718
25.3.2.1 Interaction Potential 718
25.3.2.2 Cluster Formation 720
Acknowledgements 722
References 723