**Abstract**

Carbon is a chemical element has the ability of forming long carbonic chain. Due to its special electronic structure, each carbon atom can be linked with another carbon atom or with another element via single, double or triple covalent bonds. The special electronic structure of carbon atom affecting on its properties also affecting on its ability of existing in different forms called allotropes. During few last decades, new carbon-based nanomaterials have been described including fullerene, carbon nanotube, graphene and nanodiamond. These new allotropes attracted the interest of science and industry and became as a new and important class of materials due to its outstanding features which candidate for numerous applications. In parallel with new developments in nanomedicine especially in drug delivery field, the targeted delivery systems became an important to overcome the limitations of the old fashion systems. So, it become very important to translate this idea into reality. Fullerene and nanodiamond have a unique combination of structure, morphology and biological properties that make them as a powerful tools for targeted delivery system. So, this chapter will focus on two major aspects: synthesis routes of fullerenes and nanodiamonds, and their role in nanomedicine as drug delivery systems.

**Keywords:** Fullerene, Nanodiamond, Synthesis, Properties, Drug delivery

### **1. Introduction**

Since ancient times, materials are the most interesting thing for human. In fact, human deals with different materials to meet life's requirements. Invention of new technologies requires new materials, materials with new physical, mechanical and chemical properties. Therefore, material scientists and engineers made their efforts to produce these required materials by changing their composition, structure via synthesis process [1].

In general, materials development is continuous from ancient time. So, we can notice that each period of times known by specific material's name such as: Stone Age, Bronze Age, Gold Age and Iron Age. So, due to the widespread use of nanomaterials in different industrial as well as biological fields, our current age could know by Nanotechnology Age [1].

Nanocrystalline material is one of the most interesting material with a grain size in the realm of nanometers (1–100) nm. It is not new, it is produced and used in different fields for hundreds of years. For example silver and gold nanoparticle was found in ancient paintings of glasses which gave it the ruby red color, also carbon black which is a nanostructured material was discovered in 1900 s and

used in tyres technology. These materials are bigger than single atom and smaller than a microcrystalline grain. Due to their unique structure, it exhibits unique and unprecedented mechanical, physical and chemical properties that differ from those of single atom or microcrystalline grain, these materials can be synthesized from ceramics, metals, polymers and composites [2].

At nanoscales, materials undergoing to changing in their structure, physical and chemical behaviors, these changes were driven from the several effects such as; increasing their surface area, increasing atoms concentration at grain boundaries, increasing the area of grain boundaries and decreasing the percentage of dislocations within material's structure [1–3].

On the other hand, nanotechnology was presented for the first time in 1959 at the scientific annual meeting of the American Physical Society by Nobel laureate Richard P. Feynman in the famous and classic lecture that titled "There is plenty of room at the bottom". Nanotechnology can be imagined as umbrella for all different fields and areas dealing with nanomaterials and nano objects. Furthermore, it is worth mentioning that there are several observations related to the behavior of natural nanomaterials became as inspiring and promising ideas for several applications. For example: nanofluids which has been used in different applications was inspired from blood and milk (natural nanofliud) with high dispersion stability for long periods of time [1–5].

Although nanomaterials had been known and used for many years ago, but this science gained its greatest importance after the discoveries of fullerene molecules in 1985 by Kroto's and Smalley's team [3, 6], carbon nanotubes CNTs in 1991 by Saumio Lijima [3, 7] and graphene in 2004 by Andre Geim and Kostya Novoselov [3, 8]. This fact is associated to the nanochemistry of these carbon allotropes, these nanomaterials show stability did not found in any other nanomaterials due to their high activation energy barriers. Hence they attracted a great attention of researchers to employing them in a wide variety of applications even in their nonfunctionalized state [4].

Nanomedicine-based drug delivery system has a great influence on the targeted therapy field. Via this sector of nanotechnology, the therapeutic drugs can be incorporated into a variety of bio- nanocarriers, hence, their pharmacological behavior were enhanced and leading to high treating efficiency. Nowadays, the most attracted materials in this field is the carbon- based nanomaterials [9, 10].

## **2. Carbon atom**

Carbon, denoted by letter C, is the most interested element in nature due to its abundant in universe. It is 15th most common element on earth's crust [11]. In nature, carbon's ores can be exist in different forms, as carbonates [11], wood charcoal [11], briquette and others. In human body, it is the second abundant element by mass after oxygen. Also, carbon atoms exist in all organic materials. So, it is regarded as the basic building unit for all life [11].

In periodic table, carbon atom exist in group 14, therefore it is a tetravalent. Carbon has fifteen different isotopes, two of them are stable known as 12C and 13C that comprise 98.89% and 1.11% of the carbon on earth respectively. Other isotopes known as a radio-active isotopes, among them 14C is the more stable one [12, 13].

In general, the term of electronic configuration refers to the electronic structure of an atom, with its levels, sub-levels and electrons number that occupying its orbitals. The electronic configuration of carbon atom is: 1s2 2s2 2p2 . Excited configuration is the basis of the hybrid orbital. 1s2 2s1 2px 1 2py 1 2pz 1 , hence with four unpaired electrons, four L- shell can be hybridize then and forming sp3 orbital which directed

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one [16].

*Fullerenes and Nanodiamonds for Medical Drug Delivery*

in the tetrahedral direction at angles of 109.5°. This electronic structure found in diamond. When 2 s and two of 2p orbitals hybridize together, three of the sp2 orbital was formed and directed in the trigonal direction at angles of 120° from each in a plane. This electronic structure found in graphite. While in sp. hybridization type, there is only one of 2p orbital is used which led to diagonal bonds with 180° apart. This electronic structure found in carbyne. Also it is good to mention that the

Carbon atoms have the ability to form long chain with its own atoms via feature called "catenation". There are three basic covalent bonds between carbon- carbon atoms, single bond (sigma bond) is the most common bond between carbon–carbon atoms, and it is consisting of one electron from each carbon atom and is thus a two-electron bond such as the bond in ethane. A double bonds is another type that is exist between two carbon atoms, generating the alkene group, also called olefins. These hydrocarbons are exclusively composed of carbon and hydrogen. The third type of bonding between tow carbon atoms is the triple-bond which is existing in compounds called alkynes. Due to the flexible chemistry of carbon atom and the strength of the covalent bond, carbon has the ability to create endless chains, sheets

The most prominent allotropes of carbon are graphite, diamond and lonsdaleite. Each one has its specific properties which very varying from that of another

Graphite was named by German mineralogist and chemist A.G. Wenner in 1789 [11]. It is a naturally occurring material found in a metamorphic rocks. Its structure made by holding many layers via weak forces. Each layer consisting carbon atoms arranged themselves in a honeycomb lattice [16]. Graphite is characterized by its

and three dimensional structures with different properties [14, 16].

and sp. hybridization types forming π bonds [14, 15].

*DOI: http://dx.doi.org/10.5772/intechopen.97867*

unused 2p orbital in each sp2

*Representation of carbon structures hybridization states.*

**3. Carbon allotropes**

See **Figure 1**.

**Figure 1.**

*Fullerenes and Nanodiamonds for Medical Drug Delivery DOI: http://dx.doi.org/10.5772/intechopen.97867*

*Materials at the Nanoscale*

ceramics, metals, polymers and composites [2].

of dislocations within material's structure [1–3].

for long periods of time [1–5].

functionalized state [4].

**2. Carbon atom**

used in tyres technology. These materials are bigger than single atom and smaller than a microcrystalline grain. Due to their unique structure, it exhibits unique and unprecedented mechanical, physical and chemical properties that differ from those of single atom or microcrystalline grain, these materials can be synthesized from

At nanoscales, materials undergoing to changing in their structure, physical

On the other hand, nanotechnology was presented for the first time in 1959 at the scientific annual meeting of the American Physical Society by Nobel laureate Richard P. Feynman in the famous and classic lecture that titled "There is plenty of room at the bottom". Nanotechnology can be imagined as umbrella for all different fields and areas dealing with nanomaterials and nano objects. Furthermore, it is worth mentioning that there are several observations related to the behavior of natural nanomaterials became as inspiring and promising ideas for several applications. For example: nanofluids which has been used in different applications was inspired from blood and milk (natural nanofliud) with high dispersion stability

Although nanomaterials had been known and used for many years ago, but this science gained its greatest importance after the discoveries of fullerene molecules in 1985 by Kroto's and Smalley's team [3, 6], carbon nanotubes CNTs in 1991 by Saumio Lijima [3, 7] and graphene in 2004 by Andre Geim and Kostya Novoselov [3, 8]. This fact is associated to the nanochemistry of these carbon allotropes, these nanomaterials show stability did not found in any other nanomaterials due to their high activation energy barriers. Hence they attracted a great attention of researchers to employing them in a wide variety of applications even in their non-

Nanomedicine-based drug delivery system has a great influence on the targeted

therapy field. Via this sector of nanotechnology, the therapeutic drugs can be incorporated into a variety of bio- nanocarriers, hence, their pharmacological behavior were enhanced and leading to high treating efficiency. Nowadays, the most attracted materials in this field is the carbon- based nanomaterials [9, 10].

Carbon, denoted by letter C, is the most interested element in nature due to its abundant in universe. It is 15th most common element on earth's crust [11]. In nature, carbon's ores can be exist in different forms, as carbonates [11], wood charcoal [11], briquette and others. In human body, it is the second abundant element by mass after oxygen. Also, carbon atoms exist in all organic materials. So,

In periodic table, carbon atom exist in group 14, therefore it is a tetravalent. Carbon has fifteen different isotopes, two of them are stable known as 12C and 13C that comprise 98.89% and 1.11% of the carbon on earth respectively. Other isotopes known as a radio-active isotopes, among them 14C is the more stable one [12, 13]. In general, the term of electronic configuration refers to the electronic structure of an atom, with its levels, sub-levels and electrons number that occupying its orbit-

> 2s1 2px 1 2py 1 2pz 1

 2s2 2p2

. Excited configura-

orbital which directed

, hence with four unpaired

it is regarded as the basic building unit for all life [11].

als. The electronic configuration of carbon atom is: 1s2

electrons, four L- shell can be hybridize then and forming sp3

tion is the basis of the hybrid orbital. 1s2

and chemical behaviors, these changes were driven from the several effects such as; increasing their surface area, increasing atoms concentration at grain boundaries, increasing the area of grain boundaries and decreasing the percentage

**86**

in the tetrahedral direction at angles of 109.5°. This electronic structure found in diamond. When 2 s and two of 2p orbitals hybridize together, three of the sp2 orbital was formed and directed in the trigonal direction at angles of 120° from each in a plane. This electronic structure found in graphite. While in sp. hybridization type, there is only one of 2p orbital is used which led to diagonal bonds with 180° apart. This electronic structure found in carbyne. Also it is good to mention that the unused 2p orbital in each sp2 and sp. hybridization types forming π bonds [14, 15]. See **Figure 1**.

Carbon atoms have the ability to form long chain with its own atoms via feature called "catenation". There are three basic covalent bonds between carbon- carbon atoms, single bond (sigma bond) is the most common bond between carbon–carbon atoms, and it is consisting of one electron from each carbon atom and is thus a two-electron bond such as the bond in ethane. A double bonds is another type that is exist between two carbon atoms, generating the alkene group, also called olefins. These hydrocarbons are exclusively composed of carbon and hydrogen. The third type of bonding between tow carbon atoms is the triple-bond which is existing in compounds called alkynes. Due to the flexible chemistry of carbon atom and the strength of the covalent bond, carbon has the ability to create endless chains, sheets and three dimensional structures with different properties [14, 16].
