Biomedical Applications of Graphene and 2D Nanomaterials

Md Nurunnabi, Jason McCarthy

• Publisher: Elsevier
• Year: 2019
• Print ISBN: 9780128158890
• eBook ISBN: 9780128162699
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Biomedical Applications of Graphene and 2D Nanomaterials provides a much-needed reference on the biomedical applications of 2D nanomaterials, as well as theoretical knowledge on their structure, physicochemical properties and biomedical applications. Chapters are dedicated to growth areas, such as size and shape-dependent chemical and physical properties and applications, such as in diagnostic and therapeutic products. The book also discusses the concept, development and preclinical studies of 2D nanomaterials-based biomedical tools, such as biosensors, artificial organs and photomedicine. Case studies and reports form the core of the book, making it an ideal resource on potential applications in biomedical science and engineering.This timely resource for scientists and engineers in this rapidly advancing field features contributions from over 30 leaders who address advanced methods and strategies for controlling the physical-chemical properties of 2D nanomaterials, along with expert opinions on a range of 2D nanomaterials that have therapeutic and diagnostic applications.- Presents advanced methods and strategies for controlling the physical-chemical properties of 2D nanomaterials- Provides state-of-the-art biomedical applications for 2D nanomaterials, including graphene and boron nitride- Includes key information from a broad selection of subject areas for researchers in both materials, engineering and medicine

Chapter 1

Two-Dimensional Nanomaterials: Crystal Structure and Synthesis

Khaled Parvez School of Chemistry, University of Manchester, Manchester, United Kingdom

Abstract

Since the discovery of graphene in 2004, research on two-dimensional (2-D) nanomaterials has grown exponentially in the fields of material science, condense matter physics, chemistry, and nanotechnology. The 2-D nanomaterials such as graphene, transition metal dichalcogenides, silicate clays, and hexagonal boron nitride provide enhanced physical, chemical, and biological functionality owing to their uniform shapes, high surface-to-volume ratios, and surface charge. However, research on 2-D nanomaterials is still its infancy, with majority of research focusing on elucidating unique material characteristics. To characterize the layer-dependent changes in properties and to provide pathways for their integration into a multitude of applications, it is essential to explore the reliable synthesis of single- and few-layer 2-D nanomaterials. Therefore, many synthetic strategies such as micromechanical exfoliation, liquid-phase exfoliation, and chemical vapor deposition have been developed to synthesize high-quality and ultrathin nanosheets showing their own merits and demerits in preparing 2-D nanomaterials. In this chapter, we summarize the state-of-the-art progress of this dynamically developed material family with a particular focus on their crystal structure and synthetic methods. Eventually, the potential trends and future direction for synthesizing technology for 2-D nanomaterials are proposed.

Keywords

2-D nanomaterials; Graphene

Chapter Outline

• 1 Introduction
• 2 Crystal Structures of 2-D Materials
  • 2.1 Graphene
  • 2.2 Hexagonal Boron Nitride
  • 2.3. Transition Metal Dichalcogenides
  • 2.4 Black Phosphorus
  • 2.5 Graphitic Carbon Nitride
  • 2.6 MXenes
  • 2.7 Silicene and Germanene
• 3. Synthetic Methods
  • 3.1 Micromechanical Cleavage
  • 3.2 Liquid-Phase Exfoliation
  • 3.3 Shear Exfoliation
  • 3.4 Electrochemical Exfoliation
  • 3.5 Oxidation-Assisted Exfoliation
  • 3.6 Hydro/Solvothermal Synthesis
  • 3.7 Chemical Vapor Deposition
• 4. Conclusion
• References

1 Introduction

Two-dimensional (2-D) materials have become a central topic of research interests since the exfoliation of graphene in 2004. The 2-D feature is unique and indispensable to access unprecedented physical, electronic, and chemical properties due to electron confinement in two dimensions. Graphene, a one-atom-thick and crystalline carbon film, is an exemplary model due to its unexpected properties including high carrier mobility; quantum hall effect; high specific surface area; and excellent optical, electronic, and thermal properties. Because of its remarkable properties, applications using graphene in a wide range of areas including high-speed electronics (1) and optical devices (2), energy generation and storage (3–5), hybrid materials (6), chemical sensors (7), and even DNA sequencing (8,9) have all been explored. The prerequisite for such applications is the mass production of graphene in a controlled manner because the numbers of graphene layers and the defects in these graphene layers significantly influence the subsequent properties. Methods such as mechanical exfoliation (10), liquid-phase exfoliation (11,12), electrochemical exfoliation (13–15), oxidation-assisted exfoliation (16–18), chemical vapor deposition (CVD) (19,20), and shear exfoliation (21,22) have been developed in order to make suitable graphene layers. Despite these efforts, the fine control of the number of layers and structure of graphene sheets over an entire substrate remains a major challenge.

Since the discovery of the exotic properties of graphene, the explorations of other graphene-analogous 2-D nanomaterials are also growing. To name a few, transition metal dichalcogenides (TMDCs), layered metal oxides, hexagonal boron nitride (h-BN), graphitic carbon nitride (g-C₃N₄), layered double hydroxides (LDHs), MXenes, and black phosphorus (BP) are typical graphene-like 2-D nanomaterials that exhibit versatile properties due to their similar structure features but different compositions from graphene. The common feature of these layered materials is that the bulk 3-D crystals are stacked structures. They involve van der Waals interactions between adjacent sheets with strong covalent bonding within each sheet. Such materials span the entire range of electronic structures, from insulator, to semiconductor, to metal, and display interesting properties. Because of their distinct properties and high specific surface areas, these 2-D materials are important in various applications such as optoelectronics, spintronics, catalysts, chemical and biological sensors, supercapacitors, solar cells, and lithium-ion batteries.

2 Crystal Structures of 2-D Materials

Until now, large quantities of 2-D nanomaterials have been prepared by various synthetic methods. Even though the composition and crystal structures vary in different materials, they all can be categorized into two types: layered and nonlayer-structured materials. In layered materials, the in-plane atoms connect to each other by strong chemical bonding in each layer, while these layers stack together through the van der Waals interaction. Graphite is a typical example of the layered materials in which graphene layers are stacked together forming the bulk graphite. Besides graphite, there are many layered materials, such as h-BN, TMDCs, g-C3N4, BP, and transition metal oxides (TMOs). In contrast, other materials crystallize in three dimensions via atomic or chemical bonding, forming bulk crystals, such as metal oxides and metal chalcogenides. In this section, we will introduce the crystal structures of these widely explored 2-D nanomaterials based on the composition.

2.1 Graphene

Graphene is single-atom-thick graphite, an allotrope of carbon in the form of 2-D structure. It is composed of a hexagonal close-packed carbon network, in which each atom covalently bonds to three neighboring ones through the σ-bond. The distance between two carbon atoms is about 1.42 Å. Individual layers stack together through the van der Waals force to form the graphite in which the distance between the adjacent layer is about 3.35 Å (Fig. 1) (23).

Fig. 1 Schematic illustration of (A) graphene and (B) hexagonal boron nitride (h-BN). Reproduced with permission from Ba, K.; Jiang, W.; Cheng, J. X.; Bao, J. X.; Xuan, N. N.; Sun, Y. Y.; Liu, B.; Xie, A. Z.; Wu, S. W.; Sun, Z. Z. Sci. Rep. 2017, 7, 45584, Copyright 2017 Macmillan Publishers Limited.

2.2 Hexagonal Boron Nitride

The bulk h-BN has a layered structure similar to that of graphi...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Chapter 1: Two-Dimensional Nanomaterials: Crystal Structure and Synthesis
• Chapter 2: Characterization Techniques of Two-Dimensional Nanomaterials
• Chapter 3: State-of-the-Art Characterization Methods for Graphene and Its Derivatives
• Chapter 4: 2D Nanomaterials for Gene Delivery
• Chapter 5: Graphene and 2D Materials for Phototherapy
• Chapter 6: Graphene-Based Hybrid Nanomaterials for Biomedical Applications
• Chapter 7: 2D Material-Based Hybrid Nanostructure for Diagnosis and Therapy
• Chapter 8: In Vitro Toxicity of 2D Materials
• Chapter 9: Graphene and Its Derivatives as Biosensing Platform for Healthcare Applications
• Chapter 10: Biocompatibility Assessment of Nanomaterials Using Zebra Fish as a Model
• Chapter 11: 2D Nanomaterials for Quantitative and Qualitative Analysis of DNA Methylation
• Chapter 12: Graphene-Based Electrochemical Sensors for Biomedical Applications
• Chapter 13: Nanoparticles Advancing Cancer Immunotherapy
• Chapter 14: Polymeric Surface Modification of Graphene
• Chapter 15: Graphene in Electrochemical Biosensors
• Chapter 16: Graphene in Neuroscience
• Chapter 17: Graphene-Triggered Autophagy: The Savior or Slayer
• Index