Safety Evaluation of Engineered Nanomaterials for Health Risk Assessment: An Experimental Tiered Testing Approach Using Pristine and Functionalized Carbon Nanotubes

Table 1

Physicochemical properties of nanoparticulate materials.

	MWCNTs	MW-COOH	MW-NH2	CB	SiO2
Primary particle size range (nm)	500–2000	100–300	100–300	10–20	7
Aggregate size range (nm)	≤2000*	300–1000*	300–1000*	100–1000	150–200
Specific surface area BET (m^2/g)	60	~100	~100	~240	~200
Zeta potential (mV) in deionised H2O	−44	−50	−48	−22	−30

^∗Determined by NC-AFM on samples deposited on high resolution mica sheets.