Comparative in vivo biocompatibility study of single- and multi-wall carbon nanotubes.

Carbon nanotubes are expected to be of use in both genetic engineering and biomaterials engineering. In each of these potential areas of application, nanoparticles are introduced into a living organism either in the form of active biomolecule carriers or as a result of the degradation process of an implant. In the present study we focus on the in vivo behavior of two types of carbon nanotubes (single- and multi-wall nanotubes). Raman and Fourier transform infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry techniques are used to characterize the materials before introducing them into the living system. The nanotubes were implanted into the skeletal rat muscle. A comparative analysis of the tissue reaction to the presence of the two types of carbon nanotubes was made. It was observed that multi-wall carbon nanotubes were found to form large aggregates within the living tissue, while distinctly smaller particles consisting of single-wall nanotubes were easily phagocytosed by macrophages and transported to local lymph nodes.