In vitro cytotoxicity tests of nanomaterials on 3T3 and l929 cancerous cells

Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical EngineeringIn this MS thesis, cytotoxicity tests of various nanomaterials, which have commercial applications and involve a contact with human body, were performed at different conditions. The nanomaterials used for the experiments included pristine 100 ply carbon nanowire, graphene nanoflakes, multiwall carbon nanotubes, nanoclay and C60 (buckyball or fullerene). The nanomaterials cytotoxicities were calculated and compared to each other using human and mice fibroblast cancerous cells (3T3 and L929 resp.). The in vitro MTT Assay was used as the testing method because of its simplicity and reliability. The results were analyzed by means of a spectrophotometer at 590 nm wavelength. From the optical density studies, the viabilities were calculated and the toxicities of those nanomaterials were compared. Pristine 100 ply carbon nanowire was the most viable nanomaterial with the average viability value of 86.9%. The effect of dilution on carbon nanowire was negligible which may have be due to its single dimensional threaded structure. This structure also reduced its toxicity values. However, with increase in time duration this structure became slightly weaker, and the nanowires unwound and dispersed into the media, leading to a slight increase in cytotoxicity. The concentration of the carbon nanowire at which the MTT test was conducted was 3 cm2/ml (external surface area) which weighed 18.52 mg/ml. The second most viable material after the carbon nanowire was fullerene with a viability of 75.2%. Its close packed 3D structure, negative charge and hydrophobicity may have contributed to the low cytotoxic behaviour of this nanomaterial. It was also observed that with the decrease in concentration there was a steep increase in the viability of the cells. By decreasing the concentration from 10.00 mg/ml to 2.00 mg/ml, the viability of fullerene was increased from 75% to 85%. The viabilities of other nanomaterials were in the order of multiwall carbon nanotubes (69.75%), graphene (67.48%) and nanoclay (61.34%). By decreasing the concentration from 1.10 mg/ml to 0.58 mg/ml, the viability was increased from 70% to 80%