**1. Introduction**

Carbon, which is the source of our lives, apart from our metabolic activities, attracts attention with its extraordinary structures created in nature. These structures are materials that are formed and discovered over time in the environment of high temperature and pressure [1]. The chemical properties of these materials are very different from those of inert carbon. Conductivity, strength, and catalytic properties are only a few of the carbon nanomaterials. By taking advantage of these features, the ability of today's technology to further develop products or make R&D increases. This, together with costs, can facilitate the development of technology.

With the development of biotechnology and the interdisciplinary sciences over time, the use of nanoscale materials is increasing in biotechnological process developments. Nanomaterials created new opportunities especially in biotechnology, with their easy modification advantage, especially in the field of diagnosis, and they offered significant advantages over traditional diagnostic methods in terms of sensitivity and selectivity. Diagnosis is the most important step in terms of developing health technologies. The correct diagnosis brings with it the rightful treatment, the

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 important place in today's technologies [2].

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 components [4].

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 when they are in nano form.

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 described.
