Table 1.

Physicochemical characterization of 50 nm PS-NPs

PS-NPs	SEMa (nm)	DLSb (nm)	Zeta potentialc (mV)
50 nm (0)	33.4 ± 12.7	50.0 ± 0.0	−26.0 ± 16.2
50 nm (+)	50.6 ± 9.3	50.3 ± 0.4	26.6 ± 13.9
50 nm (−M)	35.0 ± 15.3	52.7 ± 2.4	−27.7 ± 19.3
50 nm (−P)	31.6 ± 13.6	54.3 ± 0.1	−27.8 ± 17.4

(0) neutral PS-NPs, (+) positively charged PS-NPs, (−M) and (−P) negatively charged PS-NPs from Magsphere and Polysciences, respectively. Data in superscripts a and c from Walczak et al. (2014)

^aDiameters (nm) of PS-NPs in water, as measured with SEM in stock suspensions (n = 80–380)

^bHydrodynamic diameters (nm) of PS-NPs in water, as determined by DLS at t = 0 h, after re-suspending the PS-NPs in deionised water

^cZeta potential (mV) of PS-NPs in water, as determined by a zeta-sizer in stock suspensions at t = 0 h