# A Brief Review on Challenges in Design and Development of Nanorobots for Medical Applications
## 2 Challenges in the Design and Development of Nanorobots
will come together and are integrated within nanorobots structures. The traditional method of reading sensors, processing the information, designing a control scheme to send commands to actuators to minimize the error between the desired and actual values of a parameter (e.g., velocity, position, etc.) might not be feasible to be used. Instead, new methods of integrating all these together to control the response or actions of a nanorobot should be proposed. For example, as will be explained in Section 2.5, different imaging techniques can be used to localize the nanorobot inside the body, and that information can be used by the control system to send commands to the actuators or to navigate the nanorobot using variable magnetic fields. In this paper, the authors aim at explaining some challenges associated with the design and development of different robotic components such as sensors and actuators in nanoscale; however, it should be noted that, based on the structure of a nanorobot, that traditional robotics paradigm might be totally replaced by new methods. These aspects will be explained in sections after sensors and actuators. The development of nanoscale components is essential to the construction of a nanorobot; however, this is hindered by technological limitations [22]. The fabrication of a nanorobot and its application in nanomedicine is limited by two main factors: (1) the status of current technological advancements, and (2) the limitations of a nanorobot to work in micro fluids [22]. However, the first limitation has been overcome by the design and hardware control based on the progress of nanomechatronics, and with the rapid increase in advancements in nano-biotechnology, molecular manufacturing has led to the development of small-scale devices. These devices form an integral part of the nanorobot and are comprised of the main elements for sensing, actuation, the transmission of data, power supply, and control [6; 7; 8; 9]. Complementary metal-oxide-semiconductor (CMOS) technologies have aided in the manufacturing of nanoelectronics and fabricated circuits, with sizes of the features in the tens of nanometers [9]. The potential of nano processors has been demonstrated with the help of biocomputers, and advancements in nanotechnology techniques, genetics, and biomolecular computing have created a wide range of applications in medicine [9]. The second limitation--to incorporate a nanorobot in a fluidic environment--has been a critical challenge in the field of nanorobotics and its application in medicine. Therefore, various studies have shifted towards the development of microbots (A.K.A. microrobots), broadly referred to as \"swimmers\". Microbots are like their natural counterpart, and they perform well only in the presence of a nutrition or energy supply [24]. However, the application of microbots may not be feasible due to the challenges below:  
* Microprobots must harvest energy for their movement
* Microprobots must be compatible with their environmental necessities. This section discusses the various limiting factors, current research, and compatibility of a nanorobot in a biological environment.