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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
NANODIAMONDS IN ANALYTICAL AND BIOLOGICAL SCIENCES Comprehensive resource highlighting the significance and applications of fluorescent and non-fluorescent nanodiamonds in various domains Nanodiamonds in Analytical and Biological Sciences combines the disciplines of chemistry, physics, materials science, and biology to demonstrate the significance of nanodiamonds, offering precise analysis of the impacts and up-to-date applications of fluorescent and non-fluorescent nanodiamonds, including in COVID-19 and artificial intelligence, with illustrations, case studies, practical examples, and novel perspectives included throughout. Edited by two highly qualified scholars with significant experience in the field, topics covered include: * Fundamental properties, synthesis, mechanisms, and functionalization of nanodiamonds, and toxicity assessment * Fabrication and surface modification of fluorescent nanodiamonds and in vitro and in vivo bioimaging of fluorescent nanodiamonds * Nanodiamond-enabled drug delivery and nanodiamond for mass spectrometry-based analysis of peptides, proteins, and proteomes * Quantum sensing, applications in physico-chemical and biomedical sensing, and perspective and outlook on the future of nanodiamond research * Nano-scale thermometry of fluorescent nanodiamonds and nanodiamond-enabled drug delivery Offering a balanced, multidisciplinary, and comprehensive overview of the significance of fluorescent and non-fluorescent nanodiamonds, Nanodiamonds in Analytical and Biological Sciences is an essential resource for academic researchers and industry professionals working in fields spanning chemistry, physics, materials science and biology.
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Nanodiamonds in Analytical and Biological Sciences
Principles and Applications
Edited by
Wesley Wei-Wen Hsiao Department of Chemical Engineering, National Taiwan University of Science and Technology, Taiwan
Trong-Nghia Le Institute of Atomic and Molecular Sciences, Academia Sinica, Taiwan
This edition first published 2023
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To our family
Wu-Hua Hsiao, Yu-Chu Lai, Pei-Fen Lu,andYu-Ching Hsiao
Nguyen Thi Ngan, Le Thi Hong Nhung
andLe Thi Hong Hanh
for their constant and dedicated support
and to
Prof. Huan-Cheng Chang
for his valuable advice and guidance
Contents
Cover
Title Page
Copyright Page
Dedication
Contributors
Editor’s Preface: Nanodiamonds – A Rising Star in Nanotechnology
1 Nanodiamonds
1.1 Structure and Classification of Nanodiamonds
1.2 Preparation of Nanodiamonds
1.2.1 High-Pressure, High-Temperature
1.2.2 Detonation Technique
1.2.3 Chemical Vapor Deposition
1.2.4 Alternative Methods of Producing Nanodiamonds
1.3 Physical and Chemical Properties of Nanodiamonds
1.4 Colloidal Properties of Nanodiamonds
References
2 Fluorescent Nanodiamonds
2.1 Introduction to Fluorescent Nanodiamonds
2.2 Optical Properties of Fluorescent Nanodiamonds
2.2.1 Vacancy-Related Color Centers
2.2.2 Negative Nitrogen-Vacancy Center
2.2.3 Silicon-Vacancy Center
2.3 Introduction to Förster Resonance Energy Transfer
2.3.1 Theory
2.3.2 FRET Efficiency
References
3 Fabrication of Fluorescent Nanodiamonds
3.1 Introduction to FND Fabrication
3.2 Theoretical Simulations
3.3 Production and Characterization of Fluorescent Nanodiamonds
3.4 Latest Developments in High-Pressure, High-Temperature Fluorescent Nanodiamonds
3.5 Production of Ultrasmall Fluorescent Nanodiamonds
3.6 Synthesis of Highly Dispersible Fluorescent Nanodiamonds
3.7 Brightly Synthesized Fluorescent Nanodiamonds Using Solar Energy
References
4 Surface Modification of Nanodiamonds
4.1 Surface Modification of Nanodiamonds
4.2 Surface Functionalization of Nanodiamonds
4.3 Encapsulation of Nanodiamonds
4.4 Bioconjugation of Nanodiamonds
4.5 Application of Surface-Modified Nanodiamonds
4.5.1 Biotechnological Applications
4.5.2 Biomedical Applications
References
5 Toxicity Assessments of Nanodiamonds
5.1 Cellular Uptake of Fluorescent Nanodiamonds
5.2 In vitro Assessments
5.3 In vivo Assessments
5.4 Nanodiamonds’ Phytotoxic Effect
5.5 Role of Oxidative Stress in Nanodiamonds’ Toxicity
References
6 In vitro Bioimaging of Fluorescent Nanodiamonds
6.1 Bioimaging Applications
6.2 Epifluorescence and Confocal Fluorescence Imaging
6.3 Single-Particle Tracking
6.4 Two-Photon Fluorescence Imaging
6.5 Fluorescence Lifetime Imaging
6.5.1 Introduction to Fluorescence Lifetime Imaging Microscopy
6.5.2 Principles of FLIM
6.5.3 Time-Correlated Single-Photon Counting
6.5.4 FND for FLIM
6.6 Super-Resolution Fluorescence Imaging
6.6.1 Introduction to STED Microscopy
6.6.2 Principle of STED
6.6.3 FND-Enabled STED
6.6.4 Combining STED with other Techniques for Bioimaging
6.7 Optically Detected Magnetic Resonance Imaging
6.8 Cathodoluminescence Imaging
6.9 Correlative Light and Electron Microscopy
References
7 In Vivo Bioimaging of Fluorescent Nanodiamonds
7.1 Wide-Field Fluorescence Imaging
7.2 Time-Gated Fluorescence Imaging
7.3 Photoacoustic Imaging
7.4 Tissue Imaging by Microwave Modulation
7.5 Magnetically Modulated Fluorescence Imaging
7.6 Tissue Imaging Combining Microwaves and Quadruple Coils
References
8 Quantum Sensing of Fluorescent Nanodiamonds
8.1 Quantum Coherence
8.2 NV – Centers for Quantum Sensing
8.3 Emerging Sensing Technologies Using FND
8.3.1 Magnetic Field Sensor
8.3.2 Orientation Tracker for NV Axis
8.3.3 Nanoscopic Spin Probe
References
9 Nanoscale Thermometry with Fluorescent Nanodiamonds
9.1 NV Thermometry in Biosystems
9.2 Ultrahigh Precision Temperature Measurement
9.3 Time-Resolved Nanothermometry
9.4 All-Optical Luminescence Nanothermometry
9.5 Scanning Thermal Imaging
9.6 Intracellular Temperature Sensing
References
10 Nanodiamond-Enabled Drug Delivery
10.1 Introduction
10.2 Drug Delivery Through Nanodiamonds
10.2.1 Delivery of Small Molecules
10.2.2 Delivery of Peptides and Proteins
10.2.3 Gene Delivery
10.3 Fluorescent Nanodiamond-Based Theranostics Platform
References
11 Nanodiamond for Mass-Spectrometry-Based Analysis of Peptides, Proteins, and Proteomes
11.1 Principles of Analyzing Macro Biomolecules with Mass Spectrometry
11.2 The Post-Era of Genomics
11.3 Bioinformatics for the Coming of Big-Data Biology
11.4 Nanodiamonds for the Mass-Spectrometry-Based Analysis of Peptides, Proteins, and Proteomics
11.5 Origin of Interactions Between Nanodiamonds and Proteins or Peptides
11.5.1 Surface Properties of Carboxylated/Oxidized Nanodiamonds
11.5.2 Interactions of Proteins and Peptides with Carboxylated/Oxidized Nanodiamonds
11.5.3 Other Surface-Functionalized Nanodiamonds
11.6 SPEED Platform for MS-Based Study of Cellular Cytoplasmic Proteins and Human Fluids
11.7 SPEED Platform for MS-Based Study of Membrane Proteins
11.8 Surface-Functionalized Nanodiamonds for MS-Based Study of Protein Posttranslational Modifications
11.8.1 Nanodiamonds for the Selective Enrichment and MS-based Analysis of Phosphopeptides
11.9 Nanodiamonds for Enrichment and MS-Based Analysis of Glycopeptides
References
12 Emerging Roles of Artificial Intelligence in Nanodiamond Sensing
12.1 Machine Learning Algorithms for Nanodiamond Sensing
12.1.1 Support Vector Machine
12.1.2 k-Nearest Neighbors
12.1.3 Random Forest
12.1.4 Artificial Neural Network
12.1.5 Convolutional Neural Networks
12.1.6 Principal Component Analysis
12.2 Machine Learning Revolutionizes Biosensing and Disease Diagnosis
12.3 Improving Speed and Accuracy with Magnetic Field
12.4 Fluorescent-Nanodiamond-Based Immunomagnetic Microscopy of Tumors
12.5 Scaling the Nanomedicine in Clinical Research
12.6 Convolutional Neural Network Enhances Fluorescence Imaging
12.7 Challenges and Conclusion
References
13 Perspective and Outlook on Nanodiamond Research
13.1 Strengths of Fluorescent Nanodiamonds
13.2 Nanodiamond’s Surface Chemistry
13.3 Nanodiamond in Bioimaging
13.4 Nanodiamond in Quantum Sensing
13.5 Nanodiamond as Therapeutic Carrier
13.6 Nanodiamond for Biomedical Analysis
13.7 Challenges of Fluorescent Nanodiamond Research
References
Index
End User License Agreement
List of Tables
CHAPTER 01
Table 1.1 Characteristics of different...
Table 1.2 Physicochemical properties of...
Table 1.3 Comparison of properties...
CHAPTER 02
Table 2.1 Optical properties of...
CHAPTER 05
Table 5.1 In vitro and...
CHAPTER 09
Table 9.1 NV-center-based...
CHAPTER 11
Table 11.1 Number of proteins...
CHAPTER 13
Table 13.1 The strengths and...
List of Illustrations
CHAPTER 01
Figure 1.1 Structures of nanodiamond...
Figure 1.2 Classification of diamonds...
Figure 1.3 Schematic synthesized diagram...
Figure 1.4 (a) High-resolution...
Figure 1.5 SEM images CVD...
Figure 1.6 Methods for preparation...
Figure 1.7 Enhanced colloidal stability...
CHAPTER 02
Figure 2.1 Absorption and emission...
Figure 2.2 Structures of vacancy...
Figure 2.3 Energy level diagram...
Figure 2.4 Optically detected magnetic...
Figure 2.5 Principle of F...
Figure 2.6 (a) Fluorescent spectra...
Figure 2.7 FRET efficiency of...
Figure 2.8 Energy transfer efficiency...
CHAPTER 03
Figure 3.1 The interface of...
Figure 3.2 TRIM interface...
Figure 3.4 A schematic diagram...
Figure 3.5 Process of obtaining...
Figure 3.6 Size and fluorescence...
Figure 3.7 (a) Hydrodynamic diameter...
Figure 3.8 (a) Conventional and...
Figure 3.9 FND synthesis using...
CHAPTER 04
Figure 4.1 Summary of the...
Figure 4.2 (a) Silica structure...
Figure 4.3 (a) Synthesis of...
Figure 4.4 Wrap NDs in...
Figure 4.5 A scheme illustrating...
Figure 4.6 Processes of HPHT...
CHAPTER 05
Figure 5.1 In in vitro...
Figure 5.2 Variety of animal...
Figure 5.3 ND toxicity assessment...
Figure 5.4 Intensity ratio (IDia...
Figure 5.5 ROS formation (a...
Figure 5.6 ROS expression in...
CHAPTER 06
Figure 6.1 (a) Bright-field...
Figure 6.2 Single-particle tracking...
Figure 6.3 (a) Forward and...
Figure 6.4 FND tracking for...
Figure 6.5 FCS spectroscopic analysis...
Figure 6.6 (a) Typical OPE...
Figure 6.7 Time-correlated single...
Figure 6.8 Generalized set up...
Figure 6.9 Time-gating scanning...
Figure 6.10 (a) Confocal image...
Figure 6.11 Confocal (a,b...
Figure 6.12 (A) Correlative STED...
Figure 6.13 Improving spatial resolution...
Figure 6.14 The ODMR spectra...
Figure 6.15 (a) TEM images...
Figure 6.16 Internalized green and...
Figure 6.17 Plasmonic waveguides are...
Figure 6.18 (a–d...
CHAPTER 07
Figure 7.1 (a) In vivo...
Figure 7.2 Fluorescence imaging of...
Figure 7.3 Tracking the engraftment...
Figure 7.4 The photoacoustic effect...
Figure 7.5 Photoacoustic images of...
Figure 7.6 (a) Time chart...
Figure 7.7 FNDs were used...
Figure 7.8 (a) Bright-field...
Figure 7.9 ODMR-based imaging...
CHAPTER 08
Figure 8.1 Probability of finding...
Figure 8.2 Energy level diagram...
Figure 8.3 Polarization mechanism of...
Figure 8.4 ODMR spectrum of...
Figure 8.5 A single NV...
Figure 8.6 ODMR spectra (left...
Figure 8.7 Single trapped sub...
Figure 8.8 The relaxation time...
CHAPTER 09
Figure 9.1 (a) ODMR spectra...
Figure 9.2 (a) Time-resolved...
Figure 9.3 (a) Schematic diagram...
Figure 9.4 (a) Experimental setup...
Figure 9.5 (a) Confocal scan...
Figure 9.6 (A) FND-based...
CHAPTER 10
Figure 10.1 The production of...
Figure 10.2 CDDP release profile...
Figure 10.3 The production of...
Figure 10.4 Through convection-enhanced...
Figure 10.5 Therapeutic ND-EFV...
Figure 10.6 DNA4625-Cy3-TAT...
Figure 10.7 SALL4-driven HCC...
Figure 10.8 The synthesis of...
Figure 10.9 In comparison to...
Figure 10.10 High-resolution TEM...
Figure 10.11 (a) UCNPs, UCNP...
CHAPTER 11
Figure 11.1 Infrared spectra of...
Figure 11.2 Adsorption isotherms of...
Figure 11.3 SDS-PAGE analysis...
Figure 11.4 The effects of...
Figure 11.5 AP–MALDI...
Figure 11.6 Scope of typical...
Figure 11.7 MALDI-TOF mass...
Figure 11.8 Schematic representation of...
Figure 11.9 Overlapping Venn diagram...
Figure 11.10 Flowchart of extraction...
Figure 11.11 Demonstration of ND...
Figure 11.12 A general ND...
Figure 11.13 MALDI-TOF mass...
Figure 11.14 Functionalization of ND...
CHAPTER 12
Figure 12.1 A block representation...
Figure 12.2 A schematic representation...
Figure 12.3 The schematic diagrams...
Guide
Cover
Title Page
Copyright Page
Dedication
Table of Contents
Contributors
Editor’s Preface: Nanodiamonds – A Rising Star in Nanotechnology
Begin Reading
Index
End User License Agreement
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Contributors
Thi-Hong-Hanh LeDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Stefanny AngelaDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Yan-Kai TzengDepartment of Physics, Stanford University USA
Yuen Yung HuiInstitute of Atomic and Molecular Sciences, Academia Sinica Taipei Taiwan
Tan-Thanh Huynh
( and ) School of Applied Chemistry, Tra Vinh University Vietnam
Dinh Minh PhamInstitute of Biotechnology, Vietnam Academy of Science and Technology Vietnam
Duc-Thang VoCollege of Engineering, National Taiwan University of Science and Technology Taiwan
Wei-Hung ChiangDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Single-Chapter Contributors
Marvin ChenCollege of Letter and Science, the University of California, Berkeley USA
Xuan Mai Lam () Department of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Kartika WardhaniSchool of Medicine, Stanford University USA
Hsuan-Yi LinDepartment of Power Mechanical Engineering, National Tsing Hua University Taiwan
Ming-Wei JenCollege of Education and Human Ecology, The Ohio State University USA
Jo-Yu WangDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Syun-Ying WangSchool of Environmental and Biological Sciences, Rutgers University USA
Tzu-Chun YouCollege of Letter and Science, the University of California, Berkeley USA
Tzu-Syuan YouFaculty of Arts and Science, University of Toronto Canada
Yu-Teng LinDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Yen-Tse ChiangFaculty of Life Science and Medicine King’s College London UK
Neha SharmaDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Yun-Yu ChenGlobal Health and Public Policy, Duke Kunshan University China
Miranda LiuDepartment of Biomedical Engineering, Duke University USA
Richard HsinDepartment of Computer Engineering Rose-Hulman Institute of Technology USA
Raymond HsinDepartment of Biomedical Engineering, Washington University in St. Louis USA
Steven Che-Wei LuDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Ryu EndoDepartment of Biomedical Engineering, The Ohio State University USA
Chris Chen-Hua ChangDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Shahzad Ahmad QureshiDepartment of Computer and Information Sciences, Pakistan Institute of Engineering and Applied Sciences, Pakistan Centre for Mathematical Sciences Pakistan Institute of Engineering and Applied Sciences Pakistan
Haroon AmanSchool of Mathematics and Physics The University of Queensland Australia National Institute of Lasers and Optronics College, Pakistan Institute of Engineering and Applied Sciences Pakistan
Yu–Chen LinCollege of Management, National Taiwan University Taiwan
Shu-Wei ChangDepartment of Computer Science and Information Engineering, National Taiwan University Taiwan
Joshua KoDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Yu-Jou LinDepartment of Chemical Engineering National Taiwan University of Science and Technology Taiwan
Editor‛s Preface: Nanodiamonds – A Rising Star in Nanotechnology
Nanotechnology: From Big to Small
Delivered to the American Physical Society, Richard Feynman’s famous 1959 Caltech lecture, “There’s Plenty of Room at the Bottom,” is today recognized as one of the first and most influential meditations on the topic known today as nanotechnology (6). Nanotechnology is exactly what Feynman spoke of when he “theorized” the compression of massive amounts of information into tiny spaces. Today, nanotechnology is on the brink of becoming precisely what Feynman conceived: A world in which machines are too tiny to be seen.
Though many overemphasize the “nano” of nanotechnology, size is not the most important aspect of this field. Rather, emphasis is on the concept of building machines from a bottom-up perspective. As nanotechnology practitioners, we operate at the atomic level to create improved machines, materials, medicines, energy sources, and commodities. This bottom-up approach has already led to many advances in the world of science and promises to lead to many more over the next century.
Nanotechnology relies on the use of nanomaterials, which are defined as anything on a scale of 1 to 100 nm. Just as Feynman found quantum mechanics to operate at a different level than classic Newtonian physics, scientists are finding that materials often operate on the nanoscale differently than they do on the macroscale. Using these unique nano-properties, scientists develop new technologies that would have been impossible to create in the past.
Many hold the misconception that nanotechnology is a niche field, which it is not. On the contrary, nanotechnology is a multipurpose field, as its impact reaches virtually all industries and research areas.
The Nanodiamond – A Scientist’s Best Friend
A true diamond never overshadows.
It’s the brilliance of the subtle shine.
That’s most attractive.
– Dena Tyson, Xceptance, 2008
Humans have loved diamonds throughout history. On the surface, the reason is simple – they are sparkly. But the more philosophical of our ancestors gave more tangible reasons: diamonds are both rare and unbreakable. Today, researchers can synthesize diamonds, recreating the physical construction of what was once thought to be a singularity of nature.
To synthesize a diamond, we simply copy nature. In the laboratory, researchers convert graphite to physically and chemically identical diamonds found in nature through applying a high transient pressure under a high adiabatic temperature. The first proven synthetic diamond was created in 1954 by General Electric (GE) using the high-pressure, high-temperature (HPHT) method. However, as the size of this synthetic diamond was too small, with the largest size of 0.15 mm, it was applicable for the industrial field instead of gem use. Later, the first nanosized diamonds were developed by USSR in 1963. Today, these substances are known as nanodiamonds (NDs), as the commercial market (which began in the 1990s) calls it.
Modern analytical tools, such as scanning electron microscopy, infrared spectroscopy, optical microscopy, the X-ray diffraction technique, and Raman spectroscopy, help us understand the construction of NDs. The ND is unique in that it is both tiny and tough; traits that common sense often tells us are opposites. Not only are NDs used in the production of purposefully hard materials and polishing media, but they are also used in biotechnology and have the potential to play a major part in saving human lives.
As an allotrope (sp3 hybridization) of carbon, diamond has several important superlative physical properties:
It is the hardest material known to date.
It has the greatest thermal conductivity of any bulk material.
It possesses by far the highest refractive index of all dielectric materials.
Nanoscale diamonds preserve some of these properties. However, the technicalities of ND production have traditionally been expensive, time-consuming, and crude. Since 1963, NDs have been prepared by detonation to generate “detonation nanodiamonds” (DNDs). Today, manufacturers crush or ball mill micrometer or millimeter diamonds obtained by HPHT and chemical vapor deposition (CVD) to reduce production costs. Despite some differences in surface structure, the core of HPHT NDs and CVD NDs are generally similar to DNDs. DNDs are particulates (with an average diameter of 5 nm). Their primary particles have a highly uniform size distribution. Due to the large number of disordered (sp2) carbon atoms on DNDs’ surface during the synthesis period, they tend to bind together and form agglomerates. DND clusters can serve as a drug delivery system. Owing to the presence of less sp2 carbon on the surface, HPHT NDs exhibit reduced agglomeration. Therefore, even though their size distribution is broader than DNDs, HPHT NDs are amenable to many bioimaging applications. CVD NDs are thin films formed on substrates. Several industries have used these NDs as surface coating for a variety of cutting and dressing instruments.
DNDs are now taking on new roles. Biologists currently use them as diagnostic and therapeutic tools in biology and medicine, especially for nanometer-sized diamonds (1–4). Thanks to the excellent properties of biocompatibility, high loading capacity, and unique surface function, ND particles are well suited for many drug delivery applications. Another distinguishing attribute of ND is their bright, stable fluorescence, which comes from their crystals’ defects. This discovery was made in 2005 (5), and from that, a wide array of studies have been done, marking the beginning of a new era in analytical and biological applications. For instance, fluorescent nanodiamond (FND) enables the use of cell labeling, imaging, and tracking. These applications directly result from FND’s exceptionally high biocompatibility and unique optical properties (5). Recent research in the field has focused on applying surface-functionalized FNDs in bioimaging, quantum sensing, and drug or gene delivery. Results have shown that FND, with their surfaces’ function group, can conveniently be immobilized with protein or nucleic acid (5). Additionally, when exposed to green–yellow light, FND containing nitrogen-vacancy (NV) color centers can emit bright, nonphotobleaching, nonphotoblinking, tissue-penetrating red photons.
Book Structure
The design and working principles of NDs are the focus of this book. A practical understanding of this field necessitates a multidisciplinary background: Physics, chemistry, materials science, electrical and optoelectronics engineering, as well as bioengineering are all viewpoints that may be added to the ND.
This book contains 13 chapters:
Chapter 1: Nanodiamonds
Chapter 2: Fluorescent Nanodiamonds
Chapter 3: Fabrication of Fluorescent Nanodiamonds
Chapter 4: Surface Modification of Nanodiamonds
Chapter 5: Toxicity Assessments of Nanodiamonds
Chapter 6:
In Vitro
Bioimaging of Fluorescent Nanodiamonds
Chapter 7:
In Vivo
Bioimaging of Fluorescent Nanodiamonds
Chapter 8: Quantum Sensing of Fluorescent Nanodiamonds
Chapter 9: Nanoscale Thermometry with Fluorescent Nanodiamonds
Chapter 10: Nanodiamond-Enabled Drug Delivery
Chapter 11: Nanodiamond for Mass-Spectrometry-Based Analysis of Peptides, Proteins, and Proteomes
Chapter 12: Emerging Roles of Artificial Intelligence in Nanodiamond Sensing
Chapter 13: Perspective and Outlook on Nanodiamond Research
Research on the unique properties of ND/FND will likely lead scientists to find new uses for these materials, especially as particles in a multimodal imaging/therapy platform. This book touches on four major areas of ND/FND: surface modification, bioimaging, drug delivery, and quantum sensing. We hope this book can help readers choose an appropriate approach in successive ND research.
Surface Modification
As a carbon-based nanomaterial family member, NDs appear to be the most biocompatible compared with other nanoscale carbon-based materials. For this reason, biologists have begun researching their potential applications in nanomedicine (7). However, NDs or any materials practically used in biology face the following challenges: difficulties in directly modifying the NDs surface, low colloidal stability due to its aggregation in physiological media, and nonspecific protein adsorption.
In addition, colloidal stability is one of the most important features affecting the application of NDs. Like other nanoparticles (NPs), NDs’ colloidal stability is not static and can decline in solution with high ionic strength. This poses a challenge for the usage of NDs in biological systems. All physiological buffers and culture mediums have high salt content. Therefore, prior to developing analytical and biological applications, researchers must first understand the surface features and aspects of different environments. This is because these environmental interactions influence the colloidal stability of NDs.
The book examines three strategies for modifying the surface of ND: functionalization, encapsulation, and bioconjugation. We also examine the toxicity of these nanomaterials in biological systems (including both in vitro and in vivo). In this book, we focus particularly on the latest developments of surface-modified NDs in analytical chemistry, biological sciences and nanoscale medicine.
Bioimaging
Bioimaging has emerged as a major factor in mainstream life science research. Not only does it grant researchers the ability to visualize biological processes in cells and organisms, but it also allows for the real-time monitoring of molecules and cells in three dimensions – making it an incredibly useful tool in disease identification and treatment. Indeed, its noninvasiveness, sensitivity, and quantifiability have positioned bioimaging as a bastion in the field of medical research. Thanks to the tremendous research, we are now able to make a connection between the complex biochemical processes and the functioning of proteins in living cells. This stems from the decades-long effort to create molecular tags in the form of fluorescent probes. Researchers in the 2000s developed fluorescent NPs, allowing modern-day scientists to select from an array of bioimaging methods such as dye-doped nanospheres (8), quantum dots (QDs) (9), and metallic nanoclusters (10). Thanks to their unique surface properties, NDs can flexibly form bonds with many kinds of biomolecules, including peptides, antibodies, nucleic acids, or small-molecule ligands. Thus, NDs can be effectively used as fluorescent cellular markers. However, there are certain challenges associated with fluorescence bioimaging applications, including the color fading of imaging probes, photodamage to testing samples, cell autofluorescence, and strong light scattering from tissue. QDs, semiconductor NPs typically made of cadmium or selenium, are one of the most promising candidates for bioimaging. Compared with organic fluorophores, QDs have larger absorption coefficients and much higher levels of brightness and photostability. However, their inherent toxicity has hampered QDs’ use for biolabeling living cells and organisms (11). Upconversion nanoparticles (UCNPs), another attractive alternative, face similar biocompatibility issues since these inorganic nanocrystallites are doped with a transition metal, lanthanide, or actinide ions (12).
FND is the “brightest” member of the nanocarbon family. It was first shown to be useful in cellular fluorescence imaging in 2005 (13) and in in vivo stem cell tracking in 2013 (14). Surface-functionalized FNDs are gaining traction as potential optical nanoprobes for in vivo imaging, and diagnostics as technological and biomedical demands grow. FNDs allow researchers to observe, monitor, and quantify molecules and cells at a high spatial resolution – a capability that is needed in order to understand complex biological systems fully. FND-based technology has developed in tandem with the existing modern imaging modalities.
After providing a brief background of the optical properties of FNDs, this book will discuss a broad range of FND-based bioimaging technologies, including multiphoton excitation, super-resolution, cathodoluminescence, and magnetic resonance imaging. Though important, NDs as light scattering biolabels and photoacoustic contrast agents has also been discussed (15, 16).
Drug Delivery
Epidemics evolve in lockstep with human progress. At present, countries around the world are wrestling with the COVID-19 epidemic. Pandemics have serious consequences for human life and health and severe economic and world peace implications. To help us contend with disease outbreaks, identification, testing, therapy approaches, and novel vaccinations are continually being studied and presented. COVID-19 has shifted the demand for interventions directed against a single pathogen to vaccinations and therapies that can boost immune responses to groups of infections. The desire for faster vaccine development and increased worldwide access to these inoculations has also motivated the growth of drug delivery systems. Aside from COVID-19, medication and drug delivery techniques must be further developed to assist patients in overcoming various diseases, such as cancer, chronic illnesses, and other infectious diseases.
Nanotechnology has been mobilized in healthcare, particularly as medication carriers. NPs-based treatments are being researched to see if these materials can overcome the constraints of biological barriers, microenvironmental and cellular, that are heterogeneous across patient populations and diseases. The NPs’ delivery system allows the transport of hydrophobic drugs and biologics, as well as direct targeting of disease sites. In addition, NPs, with their unique physicochemical properties such as substantial loading capacities, stable quantum properties, and broad functional surface areas, enable the transport of a vast number and variety of molecules such as drugs, proteins, and genes (17).
Many NPs have been studied and used as drug delivery and monitoring carriers. They include lipid-based vehicles (e.g., liposomes, solid lipid NPs, and micelles), polymer carriers (e.g., hydrogels, polymersome, dendrimer, and nanofiber), metallic and semiconducting NPs (e.g., nanogold and QDs), carbon structures (e.g., fullerene, nanotube, graphene, and ND), and inorganic NPs (e.g., silica and metal oxides) (18, 19). However, NPs cannot work without any flaws. Due to their tiny dimensions, NPs react easily to biomolecules found in cells or in the extracellular environment, leading to unexpected or undesired biological effects. Hence, despite its potential, the use of NPs in clinical settings remains a developing research area that requires further study (20, 21).
Due to their excellent biocompatibility and nontoxicity, carbon-based nanomaterials have received more attention from biologists than metal- or semiconductor-based nanomaterials. NDs, a new class of carbon nanomaterials, have been particularly singled out as they exhibit a number of distinctive properties such as low toxicity, stable fluorescence, facile functionalization, intrinsic biocompatibility, and other fundamental properties of bulk diamonds (22). Compared with other members of the nanocarbon family, such as carbon black, carbon nanotubes, and graphene, NDs distinguish themselves by having the highest biocompatibility and lowest cytotoxicity when applied to living cells (23). Therefore, there is no doubt about the advantages of using NDs in biomedical applications. NDs of varied shapes and sizes have been created using various synthesis techniques. DNDs and HPHT NDs are commonly employed in biological studies (24). Both have excellent biocompatibility since they can remain in cells without impacting their in vitro and in vivo activities (25). DND, with a size of several nanometers, can quickly enter cell membranes in a noninvasive manner, thus preserving the cells’ integrity during the treatment period (26). This makes them ideal candidates for small chemical drug transport. In addition to their small size, NDs are notable for their abnormal reactive surface and capacity to form hydrogels, making them significant active moiety carriers in molecular biotechnologies (27).
Surface modification or functionalization of NDs with biological molecules (e.g., small molecules, peptides and proteins, genes, as well as small interfering RNA [siRNA]) is an emerging research topic in nanomedicine. These biomolecules can be flexibly attached to the surface of NDs to form the ND-X modality. ND-X modalities have been tested in both in vitro and in vivo models and can be used to target specific cells (28–30). They can also detect, monitor, and even change biochemical processes within cells. Therefore, NDs can be used as both a monitoring tool (e.g., detecting precancerous alterations) and a therapy (e.g., carrying drugs). Because of their possession of many features required for clinical applications (e.g., stability and compatibility in biological conditions, as well as scalability in manufacturing), NDs have emerged as a viable choice in many biomedical applications (5, 7, 31, 32).
The delivery of drugs is a multidisciplinary area that includes chemistry, biology, and medicine. Due to their intricacy, using NDs necessitates a vital understanding of advanced drug and gene delivery methods. Despite considerable accomplishments in recent years, ND drug delivery monitoring is still in its infancy. In this book, we will discuss the essential elements of NDs, as these materials will certainly play a crucial role in developing enhanced targeted drug delivery and monitoring systems going forward.
Quantum Sensing
Exploiting flaws in ND fragments has allowed researchers to construct precise quantum sensors in biocompatible materials (33). Quantum sensing has begun applying FNDs that contain negatively-charged nitrogen-vacancy (NV –) centers, allowing the display of quantum behavior up to room temperature.
The quantum properties of FND stem from the NV – center’s unique triplet ground state, the spin of which is susceptible to both optical detection and manipulation (34). Locked within a diamond matrix, the NV – center has a spin coherence time of up to 10 ms, even in ambient environments (35). In light of the ND’s chemical inertness and biocompatibility, FND is the perfect bridge between quantum physics and biology, unlocking new opportunities in the field of bioimaging (16). By combining the optically detected magnetic resonance (ODMR) technique and multiphoton microscopy, researchers have arrived at a possible method of creating high-resolution optical images under the skin (36). Other color centers in NDs, besides the NV center, also gain great attraction in bioimaging. The silicon-vacancy center shows particular potential, as it has a narrow near-infrared emission at 739 nm with full width at half maximum of 4 nm (37). Its magnetic features are currently the focus of research (38).
As a result of the ODMR spectrum’s sensitivity to changes in magnetic field, electric field, temperature, and pressure, ND’s NV – center is likely to be adopted in quantum sensing. The NV – center has already been operated with microwave stimulation and developed as a nanoprobe for sensing local temperature and magnetic fields. However, to broaden the range of FND applications in biomedicine, it must be developed into an all-optical nanoprobe that does not require microwave excitation (39).
This book aims to elucidate the biophysical groundwork for nanoscale – or quantum – sensing. FNDs both reveal and enhance our understanding of a wide array of topics – chemical reactions within single cells, signaling in neural networks, and the origin of magnetism – thus forming the core of this new field. Here, we begin by highlighting various “electrifying” quantum sensor applications, including magnetic field sensing, orientation tracking, nanothermometry, nanoscopic spin probes, and nuclear spin sensing.
Closing: Last but Never the Least
During the last two decades, FNDs have gained significant interest from biologists, chemists, physicists, and material scientists due to their unique structural, electrical, optical, chemical, and mechanical properties. Recently, there has been increased demand for creative industrial applications using FND. This book discusses the latest research on ND/FND synthesis and their wider applications.
This book is, undeniably, the most comprehensive reference book on FNDs. Containing plenty of illustrations, case studies, practical examples, and historical perspectives, this text will help strengthen your understanding of a variety of core concepts. Each chapter addresses, in-depth, a single integral topic. In addition to covering FND’s fundamental properties, synthesis, mechanisms, and functionalization, we also introduce a broad range of methodological concepts and techniques. Though its focus is on what has already proved workable, this book also presents a wealth of laboratory achievements and offers a profound, precise, and accessible analysis of the impacts and current applications of FNDs, up to 2022. As a result, this book is relevant to undergraduate and graduate students alike, as well as to academic researchers, industrial personnel, and instructors in biology, chemistry, physics, materials science, and other relevant fields.
The discovery of NDs/FNDs has sparked a flood of international scientific interest, and this novel material in the field of materials science and biochemical physics has revealed a cornucopia of new physics and prospective applications. Finally, we hope this book will give our readers ideas and inspiration and serve as a tremendous resource in this emerging field.
Wesley Wei-Wen Hsiao
Trong-Nghia Le
Taipei, Taiwan, August 2023
References
1
Chang H-C, Hsiao WW-W, Su M-C.
Fluorescent Nanodiamonds
. Hoboken, NJ, USA: John Wiley & Sons; 2018.
2
Hsiao WW-W, Le T-N, Chang H-C. Applications of fluorescent nanodiamond in biology. In: Meyers, R.A. (Ed.),
Encyclopedia of Analytical Chemistry
. Hoboken, NJ, USA: John Wiley & Sons; 2022. pp. 1–43,
https://doi.org/10.1002/9780470027318.a9776
.
3
Ho DE.
Nanodiamonds: Applications in Biology and Nanoscale Medicine
. Morwell: Springer; 2009.
4
Schrand AM, Hens SAC, Shenderova OA. Nanodiamond particles: Properties and perspectives for bioapplications.
Crit Rev Solid State Mater Sci
. 2009;34(1–2):18–74.
5
Vaijayanthimala V, Chang HC. Functionalized fluorescent nanodiamonds for biomedical applications.
Nanomedicine-Uk
. 2009;4(1):47–55.
6
Feynman RP. There’s plenty of room at the bottom.
Eng Sci
. 1960;23(5):22–36.
7
Xing Y, Dai LM. Nanodiamonds for nanomedicine.
Nanomedicine-Uk
. 2009;4(2):207–18.
8
Yan JL, Estevez MC, Smith JE, Wang KM., He XX, Wang L,
et al
. Dye-doped nanoparticles for bioanalysis.
Nano Today
. 2007;2(3):44–50.
9
Medintz IL, Uyeda HT, Goldman ER, Mattoussi H. Quantum dot bioconjugates for imaging, labelling and sensing.
Nat Mater
. 2005;4(6):435–46.
10
Zheng J, Nicovich PR, Dickson RM. Highly fluorescent noble-metal quantum dots.
Annu Rev Phys Chem
. 2007;58:409–31.
11
Derfus AM, Chan WCW, Bhatia SN. Probing the cytotoxicity of semiconductor quantum dots.
Nano Lett
. 2004;4(1):11–18.
12
Ang LY, Lim ME, Ong LC, Zhang Y. Applications of upconversion nanoparticles in imaging, detection and therapy.
Nanomedicine-Uk
. 2011;6(7):1273–88.
13
Yu S-J, Kang M-W, Chang H-C, Chen K-M, Yu Y-C. Bright fluorescent nanodiamonds: No photobleaching and low cytotoxicity.
J Am Chem Soc
. 2005;127(50):17604–5.
14
Wu T-J, Tzeng Y-K, Chang W-W, Cheng C-A, Kuo Y, Chien C-H,
et al
. Tracking the engraftment and regenerative capabilities of transplanted lung stem cells using fluorescent nanodiamonds.
Nat Nanotechnol
. 2013;8(9):682–9.
15
Hui YY, Cheng CL, Chang HC. Nanodiamonds for optical bioimaging.
J Phys D: Appl Phys
. 2010;43(37).
16
Hui YY, Chang HC. Recent developments and applications of nanodiamonds as versatile bioimaging agents.
J Chin Chem Soc
. 2014;61(1):67–76.
17
Niemeyer CM. Nanoparticles, proteins, and nucleic acids: Biotechnology meets materials science.
Angew Chem Int Ed
. 2001;40(22):4128–58.
18
Chow EKH, Ho D. Cancer nanomedicine: From drug delivery to imaging.
Sci Transl Med
. 2013;5(216):216rv4.
19
Koo OM, Rubinstein I, Onyuksel H. Role of nanotechnology in targeted drug delivery and imaging: A concise review.
Nanomedicine-Uk
. 2005;1(3):193–212.
20
Bae YH, Park K. Targeted drug delivery to tumors: Myths, reality and possibility.
J Control Release
. 2011;153(3):198–205.
21
Desai N. Challenges in development of nanoparticle-based therapeutics.
AAPS J
. 2012;14(2):282–95.
22
Qin J-X, Yang X-G, Lv C-F, Li Y-Z, Liu K-K, Zang J-H,
et al
. Nanodiamonds: Synthesis, properties, and applications in nanomedicine.
Mater Des
. 2021;210:110091.
23
Vaijayanthimala V, Cheng P-Y, Yeh S-H, Liu K-K, Hsiao C-H, Chao J-I,
et al
. The long-term stability and biocompatibility of fluorescent nanodiamond as an in vivo contrast agent.
Biomaterials
. 2012;33(31):7794–802.
24
Mochalin VN, Shenderova O, Ho D, Gogotsi Y. The properties and applications of nanodiamonds.
Nat Nanotechnol
. 2012;7(1):11–23.
25
Zhu Y, Li J, Li WX, Zhang Y, Yang XF, Chen N,
et al
. The biocompatibility of nanodiamonds and their application in drug delivery systems.
Theranostics
. 2012;2(3):302–12.
26
Man HB, Ho D. Diamond as a nanomedical agent for versatile applications in drug delivery, imaging, and sensing.
Phys Status Solidi A
. 2012;209(9):1609–18.
27
Man HB, Ho D. Nanodiamonds as platforms for biology and medicine.
J Lab Autom
. 2013;18(1):12–18.
28
Kaur R, Badea I. Nanodiamonds as novel nanomaterials for biomedical applications: Drug delivery and imaging systems.
Int J Nanomedicine
. 2013;8:203–20.
29
Moosa B, Fhayli K, Li S, Julfakyan K, Ezzeddine A, Khashab NM. Applications of nanodiamonds in drug delivery and catalysis.
J Nanosci Nanotechno
. 2014;14(1):332–43.
30
Perevedentseva E, Lin Y-C, Cheng C-L. A review of recent advances in nanodiamond-mediated drug delivery in cancer.
Expert Opin Drug Del
. 2021;18(3):369–82.
31
Vaijayanthimala V, Lee DK, Kim SV, Yen A, Tsai N, Ho D,
et al
. Nanodiamond-mediated drug delivery and imaging: Challenges and opportunities.
Expert Opin Drug Del
. 2014;12(5):735–49.
32
Lam R, Ho D. Nanodiamonds as vehicles for systemic and localized drug delivery.
Expert Opin Drug Del
. 2009;6(9):883–95.
33
Schirhagl R, Chang K, Loretz M, Degen CL. Nitrogen-vacancy centers in diamond: Nanoscale sensors for physics and biology.
Annu Rev Phys Chem
. 2014;65:83–105.
34
Bradac C, Gaebel T, Pakes CI, Say JM, Zvyagin AV, Rabeau JR. Effect of the nanodiamond host on a nitrogen-vacancy color-centre emission state.
Small
. 2013;9(1):132–9.
35
Rondin L, Tetienne JP, Hingant T, Roch JF, Maletinsky P, Jacques V. Magnetometry with nitrogen-vacancy defects in diamond.
Rep Prog Phys
. 2014;77(5):056503.
36
Hegyi A, Yablonovitch E. Nanodiamond molecular imaging with enhanced contrast and expanded field of view.
J Biomed Opt
. 2014;19(1):011015.
37
Aharonovich I. Diamond nanocrystals for photonics and sensing.
Jpn J Appl Phys
. 2014;53(5):05FA01.
38
Hepp C, Muller T, Waselowski V, Becker JN, Pingault B, Sternschulte H,
et al
. Electronic structure of the silicon vacancy color center in diamond.
Phys Rev Lett
. 2014;112(3):036405.
39
Plakhotnik T, Doherty MW, Cole JH, Chapman R, Manson NB. All-optical thermometry and thermal properties of the optically detected spin resonances of the NV
–
center in nanodiamond.
Nano Lett
. 2014;14(9):4989–96.
1 Nanodiamonds
Tan-Thanh Huynh, Marvin Chen, Thi-Hong-Hanh Le, Xuan Mai Lam, Kartika Wardhani, and Wesley Wei-Wen Hsiao*
* Corresponding author
Diamonds, as a carbon allotrope (sp3 hybridization), possess exceptional physical properties, such as (i) being the hardest substance known, (ii) having the highest thermal conductivity of any material, and (iii) exhibiting an extraordinarily large refractive index among dielectric materials. Some of these properties are retained, even on the nanoscale, making nanodiamonds highly versatile. Consequently, diamonds have found a new role in analytical chemistry and biological sciences. Nanodiamonds (NDs) on the nanoscale are now being used in various diagnostic and therapeutic applications. Just as diamonds are famously known as a “girl’s best friend,” NDs have rapidly become one of the most highly promising materials for scientists. Before delving into NDs’ research capabilities, this chapter summarizes the fundamental features of NDs, including structure, classification, preparation, and physical and chemical characteristics.
1.1 Structure and Classification of Nanodiamonds
NDs, also known as ultradisperse diamonds, are allotropes of nanocarbon materials, such as fullerenes, tubes, onions, rods, platelets, and graphene, with sizes in the range of several nanometers (1, 2). In the 1960s, diamond nanoparticles, or NDs, were initially manufactured in the former Soviet Union using detonation (3). Although this discovery was kept secret for nearly 20 years as a result of the Cold War, NDs created by explosive destruction have found widespread applicability in modern science and technology (4). In addition to detonation, NDs can also be synthesized by crushing or ball milling diamonds that are in the size of micrometers or millimeters, created either through high-pressure high-temperature (HPHT) or chemical vapor deposition (CVD) (5). While the lattice structure of HPHT and CVD-NDs is similar to that of NDs created via detonation (DNDs), their sizes and surface characteristics are significantly different. DNDs have a highly uniform size distribution of 5 nm. During synthesis, covalent bonding between disordered (sp2) carbon atoms on their surfaces results in densely bonded agglomerates. Biologists have been using these DND clusters as drug delivery vehicles. In contrast, HPHT-NDs are monocrystalline crystallites with exceptional optical transparency. Despite their wide size range, their lower surface sp2 carbon content results in less aggregation, thus making them more appropriate for bioimaging applications. CVD-NDs can be deposited on substrates to form thin films. Industries use these materials to form the surface coating of cutting and dressing tools.
NDs can be sorted by size into nanocrystalline (<100 nm) or ultrananocrystalline (<10 nm) (6). These substances have existed for millions of years and can be found in the earth’s sediment layers, in extraterrestrial materials, and in natural petroleum (7). ND particles are characteristically polyhedral and consist of an sp3-hybridized diamond inner core covered with an sp2-hybridized graphite outer shell or amorphous carbon that has dangling bonds with terminated functional groups on the surface. Thanks to unstable electrons around the curved surface, both graphitic (sp2) and diamonded (sp3) bonds are interchangeable. As a result, one-of-a-kind flexible templates are created. ND structure is reportedly built of two interpenetrating face-centered cubic lattices that are tightly packed (Figure 1.1). Along with the elemental cube space diagonal, one lattice is shifted by one-quarter of its length relative to the other (8).
Figure 1.1 Structures of nanodiamond from various crystallographic axes. (9) / Elsevier. Lai, Lin, and Amanda S. Barnard. Surface phase diagram and thermodynamic stability of functionalisation of nanodiamonds. Journal of Materials Chemistry 2012;22(33): 16774–16780.
Diamonds are classified into different types, as shown in Figure 1.2. Type I and type II of natural diamonds are categorized by the presence or lack of nitrogen impurities in the crystal lattice structure. Type I contains 0.001–0.3% nitrogen, while type II contains less than 1 ppm nitrogen. The distribution of nitrogen impurities further separates type I diamonds into type Ia and type Ib. Type Ia diamonds have an aggregated form of nitrogen, whereas type Ib diamonds have atomically scattered, single substitutional nitrogen impurities (C-centers). Usually, natural diamonds contain more than 1000 ppm of nitrogen in aggregate form and are classified as type Ia. Synthetic diamonds, made through the HPHT technique, with about 100 ppm of atomically isolated nitrogen, are grouped as type Ib. Type Ia is classified as type IaA, which has two aggregated nitrogen atoms (A-center); type IaB, which has platelets and four aggregated nitrogen atoms around the closed lattice vacancy (B-center); and type IaA/B, possessing the feature of both types IaA and IaB (10). On the other hand, type II diamonds continue to be categorized into type IIa, in which no impurities are present, and type IIb, which is characterized by the presence of boron atoms in the lattice structure. Type IIa is considered the purest diamond, with only 1–2% abundance. Characteristics of different types of diamonds are described in Table 1.1.
Figure 1.2 Classification of diamonds.
Table 1.1 Characteristics of different types of diamond.
Type
Feature
Color
Natural Abundance
Note
Ia
Nitrogen atom concentration up to 0.3% clustered together within the carbon lattice
Colorless, yellow
98%
Most natural diamonds
Ib
Nitrogen atom concentration up to 500 ppm, spread evenly throughout the carbon lattice
Yellow, orange, brown
0.1%
Almost all synthetic diamonds
IIa
No or few nitrogen atoms
Colorless, yellow, brown, pink, purple
1–2%
The “purest” diamonds
IIb
No or little nitrogen but boron contained in the p-type semiconductor
Blue, gray
0.1%
1.2 Preparation of Nanodiamonds
Diamonds have a metastable structure at standard temperature and pressure and are much less thermodynamically stable than its common allotrope, graphite. Therefore, diamonds are generally formed in nature in the lithospheric mantle at more than 140 km depth. In industrial production, diamonds can be synthesized via the HPHT growth technique, detonation synthesis, or the CVD method. HPHT NDs (Figure 1.3a) are gained through a “top-down” process by crushing an HPHT diamond and subjecting it to a levigation procedure under high pressure and temperature in a hydraulic press using metal catalysts. HPHT NDs consist of substitutional nitrogen impurities, which lead to highly fluorescent nitrogen-vacancy (NV) centers upon appropriate treatment. As a result, they have been found to be particularly useful biomarkers. DNDs (Figure 1.3b) are monodisperse particles formed by the controlled detonation of carbon-containing suitable precursors such as combined trinitrotoluene (TNT) and hexogen (RDX) in a closed chamber in the absence of oxygen. CVD NDs can be produced on distinct substrates by forming nanocrystalline and ultracrystalline films. CVD (Figure 1.3c) grows diamonds by employing low-pressure carbon-containing gasses. The melting temperature (at the process pressure) of the substrate must be greater than that of the necessary deposition temperature for diamond growth (usually higher than 700 °C) to facilitate the formation of the diamond rather than amorphous carbon. CVD NDs are particularly suitable for manufacturing biocompatible coatings with excellent mechanical and wear-resistant properties for biosensor applications after the appropriate surface modification with specific biochemicals.
Figure 1.3 Schematic synthesized diagram of (a) HPHT ND, (b) DND, and (c) CVD processes. Source: Reproduced from ref. (9) / AIP Publishing LLC.
Historically, the first reported NDs to be used were DNDs (11). In comparison, CVD and HPHT synthesis under frequent conditions of 1400 °C and 5–6 GPa are the predominant industrial methods for current synthetic ND production. These approaches are often used to form micron-sized or bigger diamonds that can be processed to yield NDs. NDs, on the other hand, can also be produced by the detonation of explosives in sealed containers, which produces DNDs with a diameter ranging from 4 to 7 nm (12, 13). Diamondoids, such as adamantane, which are naturally found in crude oil, are the tiniest conceivable diamonds. Many other approaches can be used to obtain bigger NDs with a diameter of up to 100 nm.
1.2.1 High-Pressure, High-Temperature
The synthesis of “man-made diamonds” using the HPHT transformation of graphite was first described in 1955 by researchers from General Electric (9). In this method, a hydraulic press is used to create a pressure of 5–11 GPa. While keeping a temperature in the range of 1200–2200 °C, a metal catalyst, typically group VIII-transition metals, i.e., Fe, Co, Ni, and their alloys, is added to accelerate the process of converting graphite powder into diamond (14, 15). Recent studies have expanded the catalyst class to include Mg-based or 15 rare-earth metals (16, 17). The diamond crystals obtained by the HPHT technique possess blocky shapes with the primary particle size ranging from 10 nm to about 1 cm. One limitation of the HPHT method is that most diamonds produced by this technique are type Ib. Their single substitutional nitrogen atom concentration in the crystal lattice (100–200 ppm), as natural impurities, results in a color change to yellowish or yellow–orange tones leading to the limiting the applications (18, 19). These “man-made diamonds” can be differentiated from natural type Ia diamonds by determining the concentration of nitrogen impurities (Table 1.1). Irradiation of type Ib HPHT diamonds with high-energy electrons, protons, and helium ions, followed by thermal annealing, results in the formation of negatively charged NV centers with red emissions, leading to the production of fluorescent NDs (FNDs) (15). HPHT diamonds are monocrystalline and are of high enough quality to be used for various industrial operations, such as the cutting and machining of mechanical components, as well as the polishing and grinding of optics (larger HPHT diamonds can also be used as gemstones). Type Ib HPHT diamonds contain only diamond carbon structures (e.g., diamond-like carbon [DLC], graphite, and amorphous carbon).
1.2.2 Detonation Technique
In 1963, a group of Soviet Union scientists discovered single crystals of diamond particles in soot-formed and so-called detonation diamonds (DNDs) by detonating an oxygen-deficient TNT/RDX mixture composition in an inert media (3, 1). From the 1980s onward, DNDs have attracted the interest of a growing number of researchers (20). DNDs have the smallest particle sizes among particulate synthetic diamonds, with an average primary size of roughly 5 nm (21). As a result of shock-wave propagation, the carbon is squeezed into crystalline grains of diamond, which is produced by an intense explosion within only a fraction of a microsecond in an oxygen-deficient atmosphere. However, until recently, the applications of DNDs remained relatively unexplored due to USSR security restrictions and a lack of contemporary interest in nanotechnology. Over the past decade, there has been a noticeable interest in the use of DND particles for various commercial applications, such as quantum computing (22), catalysis (23), lubrication (24), microelectronics (25), electrochemistry (26), and biomedicine (27, 28). Two other examples of DND applications are the formation of hard coating composites (29, 30) and the polishing and seeding of substrates for CVD diamond growth (31, 32).
DND particles can have a size of up to 200 nm due to harsh explosion states in the reactor that inevitably induce significant particle aggregation. In addition to electrostatic interaction, particles are linked by covalent bonds between surface functional groups and soot structures around each primary particle (Figure 1.4). To generate a graphite-free diamond, rigorous purification of the soot is necessary. Figure 1.4b depicts a structural model of the unusually strong DND agglomeration. The primary diamond particles are surrounded by graphitic and soot-like material. To refine the primary particles of DND with a size of 4–5 nm and minimal amounts of sp2 carbon impurities, intricate postprocessing deagglomeration and purification can be applied to break the disordered sp-sp2 bonded carbon atoms on the surfaces. Methods including wet ball milling with ZrO2 microbeads (33) and annealing in different atmospheres are then introduced (34). As a result, the primary particles of DND are readily available in kilogram amounts in the forms of colloidal sols, gels, and assemblies, which are suitable for a variety of applications.
Figure 1.4 (a) High-resolution TEM image of typical clusters of DNDs. The particles are surrounded by graphitic and soot-like material. (b) Structure model of the diamond agglomerates. Source: Reproduced from ref. (35) / John Wiley & Sons.
1.2.3 Chemical Vapor Deposition
Diamond growth through CVD emerged in the 1950s. CVD is one of the most versatile thin-film deposition techniques employed for nanocrystalline diamond film synthesis. However, in early CVD experimental setups, the growth rate was low due to the deposition of graphite, which led to mixed sp3/sp2 phases (36). This would change with the breakthrough discovery of Angus et al., who found that the presence of a large proportion of atomic hydrogen in the gas mixtures leads to the preferential etching of graphite, resulting in increased diamond growth (37, 38). As a result, CVD diamond growth has become an active and extensive area of research that has, since the early 1980s, led to the industrial manufacture and the utilization of diamond materials in various applications.
The CVD process begins with the carbon-containing precursors’ dissociation above a solid substrate surface, followed by the reaction of the decomposition products with the production of a diamond layer, which causes diamond deposition onto that surface. Methane is a common carbon source for diamond formation, although other carbon-containing gasses can also be used. CVD diamond growth requires a means of activation for the precursor molecules (methane or other hydrocarbons) diluted in a surplus of hydrogen, which is typically carried out using thermal methods (e.g., a hot filament), electric discharge (e.g., direct current plasma jet, radio frequency, or microwave plasma-enhanced CVD), or a combustion flame (e.g., oxyacetylene torch) (39). The typical methane concentration in the gas mixture ranges from 0.5% to 2%. During diamond growth, the decomposed methane or other hydrocarbon molecules are exclusively responsible for carbon supply, while atomic hydrogen is the most crucial component of the gas phase mixture, which terminates the “dangling” carbon bonds on the surface of the growing diamond or diamond nuclei to prevent the formation of graphite (sp2 bonds) and promote diamond growth (sp3 bonds). Scanning electron microscopic (SEM) images CVD diamond film deposited at various CH4/H2 ratios are shown in Figure 1.5.
Figure 1.5 SEM images CVD diamond film deposited at various CH4/H2 ratios (a and f) 0.5, (b and g) 1.0, (c and h) 1.5, (d and i) 2.0, and (e and j) 2.5 vol% at 1073 K. Source: Reproduced from ref. (40) / Royal Society of Chemistry.
