Carbon nanotubes biological applications

Bianco A, Prato M (2003) Can carbon nanotubes be considered useful tools for biological applications Adv. Mater. 15 1765-1768. 

Carbon electrodes can be made from a number of various crystalline forms of carbon. The two most common versions are the carbon paste electrode and the glassy carbon electrode. In Chapter 11, devoted to the electrochemistry of biological functions, it will be seen that pyrolytic graphite electrodes have also found wide application. Recently, attempts to use carbon-nanotube electrodes have been also proposed.9... 

A. Bianco, K. J. Kostarelos, M. Prato, Applications of carbon nanotubes in drug delivery, Current Opinion in Chemical Biology, vol. 9, pp. 674-679, 2005. 

Other alternatives for the construction of CNT based FETs have been explored. For example, carbon nanotube branches with Y shape can be used directly as transistors where the modulation of the current from an ON to an OFF state is presumably mediated by the defects and the morphology of the junction (see Fig. 19) [170, 171]. Carbon nanotube based FETs can be gated by an electrode immersed in a solution, or by charged molecules in solution (proteins, DNA, etc.) which opens a huge field of applications in sensors [172-176] (see Fig. 20). Their ability to operate under biological conditions allows their direct use or integration into biological systems [177]. 

Carbon nanotubes are unique materials with specific properties [42]. There is a considerable application potential for using nanotubes in the biomedical field. However, when such materials are considered for application in biomedical implants, transport of medicines and vaccines or as biosensors, their biocompatibility needs to be established. Other carbon materials show remarkable long-term biocompatibility and biological action for use as medical devices. Preliminary data on biocompatibility of nanotubes and other novel nanostructured materials demonstrate that we have to pay attention to their possible adverse effects when then-biomedical applications are considered. 

It is obvious that we are at the stage of accumulating the knowledge of how to handle safely nanosized objects. Carbon nanotubes are currently and will be in the future at the forefront among other known nanomaterials, in terms of volumes of research, manufacturing and applications in various fields of practical activities, including medicine and biology. 

NONCOVALENT FUNCTIONALIZATION OF SINGLE-WALLED CARBON NANOTUBES FOR BIOLOGICAL APPLICATION RAMAN AND NIR ABSORPTION SPECTROSCOPY... 

In many cases the potential application of single-walled carbon nanotubes is associated with solubility of this nanomaterial in different solvents. Unfortunately, nanotubes are poorly soluble in the most of organic solvents and are insoluble in water, and this fact especially hinders biological using SWNT. Weak solubility of SWNT is a result of substantial van der Waals attractions between nanotubes aggregated in bundles. To solve nanotubes in water without any covalent functionalization, a surfactant would be added into aqueous solution, and then this mixture is suspended by sonication. It is supposed that the sound wave splits bundles in aqueous solution. A surfactant in suspension adsorbed onto the nanotube surfaces precludes aggregation of nanotubes in bundles. 

These examples of functionalization of carbon nanotubes demonstrate that the chemistry of this new class of molecules represents a promising field within nanochemistry. Functionalization provides for the potential for the manipulation of their unique properties, which can be tuned and coupled with those of other classes of materials. The surface chemistry of SWCNTs allows for dispersibility, purification, solubilization, biocompatibility and separation of these nanostructures. Additionally, derivatization allows for site-selective nanochemistry applications such as self-assembly, shows potential as catalytic supports, biological transport vesicles, demonstrates novel charge-transfer properties and allows the construction of functional nanoarchitectures, nanocomposites and nanocircuits. 

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