Computational studies of carbon nanostructures: gas sensing and immunotoxicity

During the past three decades carbon nanostructures including fullerenes, carbon nanotubes (CNTs), and graphene have been given a prominent place in the field of nanoscience and nanotechnology. Thus, the unique characteristics of carbon nanotubes such as high tensile strength, ultra-high stiffness, high current carrying capacity, and high thermal conducting ability make them very attractive material in different areas of science and engineering, including chemistry, materials science, biomedicine etc. Considering environmental issues, carbon nanotubes are expected to be a light-weight, miniature gas sensors for reliable detection of wide variety of gases and chemical vapors such as NO₂, O₂, NH₃, N_2, CO₂, H₂, CH₄, CO, H₂O. The interaction of NH₃ with CNTs stimulated interest since it is somewhat controversial. Thus, chemisorption of NH₃ on model single walled carbon nanotubes (SWCNTs) with and without Stone Wales defect (SWD) was confirmed to be marginally exothermic and endothermic respectively. In order to understand the influence of Stone-Wales defect and its orientation in (5,5) SWCNT for detection of NH₃ gas by chemisorption mechanism we have performed more detailed studies.

Toxicological risk assessment of occupational exposures to manufactured carbon nanoparticles is very complex and requires contributions from researchers representing many disciplines. Recent studies on CNTs and fullerenes showed a certain level of toxicity in mammals, and particularly in humans. Numerous experiments indicate that carbon nanostructures cause perturbations in immune systems and limit their application in biomedicine. Although the number of reports is rapidly growing, there is still lack of knowledge on the potential toxicity of such materials to immune system and the associated mechanism is yet to be understood. Based on the experimental immunotoxicity data, we suggested a hypothetical model providing the potential mechanistic explanation for immune and inflammatory responses observed upon exposure to carbon nanoparticles.