Natural Transformation of Zinc Oxide Nanoparticles and Their Cytotoxicity and Mutagenicity

Table 1

Particle size and zinc concentration of pristine and alkalized NPs suspension.

NPs with different alkalization time	Hydrodynamic size (nm)		Zn concentration in NP stock suspension (μg/mL)
	Stock suspension	F-12/8% FBS
Pristine			4.8970
20 days			9.1402
60 days			13.8040
120 days			28.1730

Nanoparticle size was expressed as intensity-based average hydrodynamic diameter. Bars: ±SD. The dissolved Zn concentration was measured by ICP-OES: 50 mg/mL NPs was suspended in Milli-Q water at 25°C. After high-speed centrifugation (20,000 rpm for 30 min with cooling) and membrane filtration (Whatman alumina Anotop membrane, 0.02 μm pore size, 47 mm diameter), the concentration of elemental Zn (206.200 nm) in the supernatants was measured using ICP-OES.