A Comparative Study of Short Multi-Walled Carbon Nanotubes with Different Bulk Densities

Multi-walled carbon nanotubes (MWNTs) were investigated before and after carboxylic acid functionalization. Here, the comparative analysis of MWNTs with different bulk densities reveals similar Raman and FTIR spectra before and after acid functionalization except for minor differences. However thermal analyses exhibited some basic differences for both MWNTs before and after acid treatment. We investigated the cytotoxicity of two MWNTs on HT-29 and HEK293-T cells through three different methods: MTT assay, DAPI staining, and xCELLigence real-time cell analyzing method. It was observed that high bulk density affects the cytotoxicity for both cell lines and in all methods. Because the acid treatment lowered the bulk density, after acid treatment, the MWNTs with the higher bulk density (C150P) elicited similar cytotoxicity compared to the lower one (C70P).