Table 1.

Silica nanoparticle characterization. Nanoparticle properties (stock suspension concentration, size, surface charge, particles per milliliter, particles per gram, composition, synthesis, and porosity)

	10SiNP	50SiNP	150SiNP	500SiNP
Concentration (mg/mL)*	50.0	57.0	100.0	100.0
Size (nm)*	10.0	50.0	150.0	500.0
Size (nm)†	10.50 ± 0.19	52.67 ± 0.66	148.20 ± 2.19	495.90 ± 5.87
Surface charge*	Negative	Negative	Negative	Negative
Zeta potential (mV)#	−43.44 ± 1.75	−38.33 ± 0.20	−38.43 ± 0.30	−39.29 ± 0.12
Particles per mL*	4.90 × 1016	3.92 × 1014	2.99 × 1013	7.42 × 1011
Particles per gram*	9.55 × 1017	7.64 × 1015	2.83 × 1014	7.20 × 1012
Composition*	Pure SiO2	Pure SiO2	Pure SiO2	Pure SiO2
Synthesis*	Precipitated	Precipitated	Precipitated	Precipitated
Synthesis*	Colloidal	Colloidal	–	–
Porosity*	Nonporous	Nonporous	Nonporous	Nonporous

^*Notes: Supplied by the manufacturer, as well as re-evaluated by

^†transmission electron microscopy (size) and by

^#Zetasizer (zeta potential) in ultrapure water.

Abbreviation: SiNP, silica nanoparticles.