In Vitro Cytotoxicity of Multiwalled and Single-Walled Carbon Nanotubes on Human Cell Lines

Carbon nanotubes are the building blocks for future electronics, materials, health care devices etc. In order to explore the health care applications of nanotubes in diagnosis and drug delivery, it is important to understand their toxicity. In the present study the in vitro responses were seen when carbon nanotubes were exposed to human cell lines. It typically involves dispersion of multiwall and single walled carbon nanotubes, as well as carbon black and quartz as reference material within the cell culture medium followed by their subsequent addition to human cell lines. MTT 3-(4, 5 dimethylthiazol-2 yl) 2, 5-diphenyl tetrazolium bromide, a tetrazole assay was performed; cell viability was measured by observing their absorbance using ELISA (enzyme-linked immunosorbent assay) reader. Cell viabilities at different concentrations i.e. 50, 10, 5, 3, 1 mu g mL(-1) were studied. In MTT assay, it was observed that cell viability increases with decrease in concentration of single walled and multiwall carbon nanotubes. We found that both behave almost in the same manner in terms of viability in case of MTT assay. Cellular uptake of FITC (fluorescein isothiocyanate) labeled carbon nanotubes were imaged using confocal microscopy and transmission electron microscope.