Two faces of carbon nanotube: toxicities and pharmaceutical applications.

In the field of nanotechnology, carbon nanotube (CNT) is gaining importance for the delivery of therapeutic agents and diagnosis of diseases. CNT is emerging as an efficient nanocarrier system with cylindrical nanostructure. Due to its nanoscale dimensions, CNTs have a high cell-penetration quality that allows its use in site-specific targeting. Another aspect of the utilization of CNT lies in its hollow structure through which an active moiety can be delivered in a controlled manner via CNTs' nano channels. Despite these positive aspects of CNT, scientists are still working to improve its biocompatibility and solubility and eliminating toxicity in vivo, which are creating problems with the use of CNTs. Therefore, functionalization becomes an important aspect to be studied because it decreases the toxicity of CNTs and make them nonimmunogenic. In this review, different functionalization techniques of CNTs and their biomedical applications-in particular for cancer therapy to date-are reviewed in detail to present the potential of this nanovector.