Table 1.

Physicochemical properties of AuNPs

NP	HD-water(nm)	HD-1xPBS(nm)	ZP(mV)	Tf content(# Tf/particle)
I	49.4 ± 0.6	755.4 ± 8.7	−18.3 ± 1.2	N/A
II	73.2 ± 1.3	74.9 ± 0.9	−10.9 ± 1.3	N/A
III	77.0 ± 0.9	77.7 ± 1.5	−10.8 ± 0.9	2.1 ± 0.2
IV	78.5 ± 1.7	81.3 ± 2.9	−9.0 ± 1.7	17.5 ± 2.5
V	81.0 ± 2.5	87.5 ± 3.4	−9.9 ± 1.7	144.3 ± 15.6

I, unmodified AuNP; II, PEG-AuNP; III–V, Tf-PEG-AuNP of 2, 18, and 144 Tf per particle, respectively; HD, hydrodynamic diameter; N/A, not applicable; NP, nanoparticle; ZP, ζ potential in 1 mM KCl. The table presents data as average ± SD from three experiments.