# A Brief Review on Challenges in Design and Development of Nanorobots for Medical Applications
## 3 Challenges in the Application of Nanorobots
Bio nanocomposites with inorganic materials have also been developed, and these include bioactive glass nanoparticles, magnetic nanoparticles, carbon nanotubes, hydroxyapatite, silver or gold nanoparticles, graphene oxide, titanium oxide, and silica nanoparticles [15]. Figure 6 shows some medical procedures performed by nanorobots. Figure 7 shows application of nanorobots in dentistry. One of the most promising areas in which nanorobots may play a vital, life-altering role is in the treatment of injuries related to spinal cord and nerve damage. The regeneration of axons using enriched scaffolds and the improvement of nerve reconnections is feasible with nanotechnology. The axon surgery has been demonstrated to effectively possible with the use of a 40 nm diameter nano knife, which aided in the individual manipulation of axons [20]. The movement of axons under precise control was achieved by a process known as dielectrophoresis; this method uses electric fields to control and move objects in  
Figure 6: Different medical procedures performed by nanorobots: (**a**) Nanorobots for biopsy, (**b**) Nanorobots for sensing and imaging of cells and tissues inside the human body, (**c**) Nanorobots for the delivery of drugs to targeted cells. surgical fields. Once the axons are positioned by this process, an electrofusion technique is used to fuse the ends of axons. Other techniques used for fusion include laser-induced cell fusion or polyethylene glycol. Figure 8 shows the application of nanorobots for selective destruction of cancer cells. One of the prominent applications of nanorobots is the ability to reconnect nerves with precise control. It was reported that, once their cerebral aneurysm ruptures, ten individuals die before reaching the hospital, 25 die within 24 h, and 50 die within the span of 30 days. To prevent these outcomes, nanorobots were incorporated to monitor and screen for the development of new aneurysms inside the human body [131]. The use of nanorobots would advance biomedical operations such as minimally invasive surgery, aid patients who require continuous supervision of body function and increase care quality by early detection of potentially serious diseases [21]. Patient screening would better prepare for neurosurgery, early-stage cancer detection reports, and blood pressure management in patients with cardiac problems [117; 118; 119; 132]. This exact technique can be used to monitor blood glucose levels in patients with diabetes [120; 121]. Improper regulation of blood glucose may have a wide range of effects on the nervous system, the liver, and the lungs and can increase the risk of heart attack and stroke [133]. Valuable data collected by a nanorobot would help clinicians track and enhance the intake of the  
Figure 8: Nanorobots for selective destruction of cancer cells. Figure 7: Nanorobots in dentistry for the treatment of hypersensitivity. patient's drug and diet. After this process, the nanorobot would be removed or disposed of according to instructions. Wearable technologies have been the focus of many research studies in recent years. With advancements in design and manufacturing new sensors, actuators, and processors, combination of wearable technologies with nanorobots is becoming a possibility in near future for medical applications. Wearable technologies can boost the development and application of nanorobots in medicine as the level of uptake in societies has shown promising results. This fact can in turn boost investments in the field of nanorobots and further help in new enhancements in the technology itself. To conclude, even by considering recent advancements in the field of nanorobots, this field is still far away from being used in clinical applications. Issues related to biocompatibility and toxicity and the risks associated with the introduction of such robots in the body are still outstanding and need proper consideration and experimental research studies.