**2. Fullerenes**

#### **2.1 Fullerene structure**

Production and applications of carbon-based nanomaterials have gained speed in recent years. Carbon nanomaterials that can be found in different conformations with Sp2 hybridization can be extremely useful (**Figure 1**). These nanomaterials include nanotubes, graphene, carbon nanoparticles, carbon fibers, and fullerenes [7]. Among these materials, fullerenes are nanomaterials that have gained speed in recent years due to their structure and unique properties.

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*Fullerene Based Sensor and Biosensor Technologies DOI: http://dx.doi.org/10.5772/intechopen.93316*

carbon structures fused together [1].

*General structure of the graphene and fullerene.*

**2.2 Fullerene derivatives and chemical reactions**

fullerene derivatives.

**Figure 1.**

solvents were examined [11].

group-modified transducer.

Fullerenes are spherical carbon nanomaterial derivatives. This structure, unlike other carbon structures, consists of a closed form of pentagonal and hexagonal

The most isomerically found types of fullerene derivatives are C60 and C70 fullerenes. These derivatives can only be dissolved in highly non-polar liquids such as toluene and benzene. Thanks to this hydrophobic property, it can be used as a drug carrier, intercalator or modification material in hydrophobic layers as lipid layers. In computer studies about fullerene, solubility attempts that were made in 75 different

Although it is possible to dissolve in different solvents, surface modification of fullerenes for biosensor and sensor technology is the most effective way to use fullerene. The solubility in water can be achieved by being modified with polar groups. The method developed by Hirsch and colleagues, fullerene was modified by 18 carboxyl groups, gained solubility in water as 34 mg/mL at pH = 7.4 [12]. In these studies, a nucleophilic cyclopropanation procedure was performed; the protection was removed with the help of bis-(polyamide)-malonate dendrimer; and 18 carboxyl groups were created (**Figure 2**). With this modification, a material, which can be used as an advantage in water solubility for modification of the carboxyl group, especially for sensor and biosensor technology, is obtained. With the activation of EDC/NHS, 18 carboxyl groups can be made to bind the amino group or a fullerene nanomaterial containing carboxyl groups can be modified on an amino

Graphene nanomaterials are called two-dimensional nanomaterials because they consist of only one layer, while fullerenes are classified as zero dimensional closed cage type nanomaterial. The spherical form of the fullerene nanomaterial gives this nanomaterial a large surface area [8–10]. This feature is a sought after feature for biosensors and sensor systems. The most advantageous feature of the double bonds formed by the carbon structure is that they can be modified as they can easily respond to chemical reactions. Most of the chemical reactions occurred by the nucleophilic attacks can form active sides on the fullerene sphere. With these modifications, fullerenes can be chemically modified. Chemical modification is important for biomolecule immobilization or surface modification. Fullerene in 60 carbons has the capacity to form 30 bonds due to its spherical structure and 30 double bonds. These bonds can be modified with different chemical agents to form

*Fullerene Based Sensor and Biosensor Technologies DOI: http://dx.doi.org/10.5772/intechopen.93316*

*Smart Nanosystems for Biomedicine, Optoelectronics and Catalysis*

important place in today's technologies [2].

components [4].

when they are in nano form.

described.

**2. Fullerenes**

**2.1 Fullerene structure**

due to their structure and unique properties.

right prognosis, the well-being of the patient, and the decrease in health expenditures. The important parameters in the exact diagnosis are sensitivity and accuracy. These two terms can describe the technological power of the diagnostic systems. In the development of sensitivity and accurate measurement, nanomaterials have an

Among the various nanomaterials, carbon nanomaterials offer wide advantages due to their outstanding electrical, thermal, chemical, and mechanical properties [3]. Composite materials derived from carbon nanomaterials are used in energy storage and conversion, sensors, drug delivery, field emission, and nanoscale electronic

Depending on the purpose of use, carbon nanomaterials increase sensitivity by increasing surface area and conductivity especially in diagnostic systems. A promising sub-branch of diagnostic systems has made great progress in recent years, creating an important area in the development of point-of-care diagnostic tests. This area is especially developed on the fundamentals of sensor and biosensor technology. The technology consists of a recognition agent placed on a physicochemical transducer. In this simple system, electrodes, optic systems, or piezoelectric systems can be used as physicochemical transducers. Electrodes are physicochemical conductors that can detect electrochemical signals in a solution. On the other hand, optical sensors can detect light-matter interactions, and piezoelectric systems can perform specific and sensitive mass analysis. The recognition layer on these transducers plays a key role for biosensors and sensors. In biosensor systems, this recognition receptor is called biorecognition agent such as enzymes, antibodies, DNA, RNA, and other proteins that can be used as biorecognition elements [5]. As a result of the interaction of these biomolecules with the target molecule, catalytic or affinity-based biosensor systems can be developed. Otherwise, molecularly imprinted polymers, nanoparticles, and other polymers can be used as recognition agents in sensor systems instead of biological receptors [6]. Increasing the effectiveness of these recognition agents depends entirely on the properties of the immobilization/modification material used in the modification of the physicochemical transducer. Fortunately, nanomaterials can be used in sensor and biosensor systems in order to increase the power of the measurement system or to use it as recognition materials. These materials increase the surface area to obtain more sensitive signals and increase the possibility of interacting with more target molecules by binding more recognition agents to the surface. Technically, nanomaterial forms of inert metal/organic materials can be used as catalytic agents

In this book chapter, the production method, modification, and use of fullerene nanomaterials, which is a nanomaterial in the development of biosensor and sensor systems developed with biological or non-biological recognition agents, are

Production and applications of carbon-based nanomaterials have gained speed in recent years. Carbon nanomaterials that can be found in different conformations with Sp2 hybridization can be extremely useful (**Figure 1**). These nanomaterials include nanotubes, graphene, carbon nanoparticles, carbon fibers, and fullerenes [7]. Among these materials, fullerenes are nanomaterials that have gained speed in recent years

**62**

**Figure 1.** *General structure of the graphene and fullerene.*

Fullerenes are spherical carbon nanomaterial derivatives. This structure, unlike other carbon structures, consists of a closed form of pentagonal and hexagonal carbon structures fused together [1].

Graphene nanomaterials are called two-dimensional nanomaterials because they consist of only one layer, while fullerenes are classified as zero dimensional closed cage type nanomaterial. The spherical form of the fullerene nanomaterial gives this nanomaterial a large surface area [8–10]. This feature is a sought after feature for biosensors and sensor systems. The most advantageous feature of the double bonds formed by the carbon structure is that they can be modified as they can easily respond to chemical reactions. Most of the chemical reactions occurred by the nucleophilic attacks can form active sides on the fullerene sphere. With these modifications, fullerenes can be chemically modified. Chemical modification is important for biomolecule immobilization or surface modification. Fullerene in 60 carbons has the capacity to form 30 bonds due to its spherical structure and 30 double bonds. These bonds can be modified with different chemical agents to form fullerene derivatives.
