The size and shape of the AP205 VLP in phosphate buffer saline (PBS, 1x, 137 mM, 2.7 mM KCl, 10.1 mM Na2HPO4 2H2O, and 1.8 mM KH2PO4) at pH 7.4 were analyzed with SAXS, DLS, and zeta potential measurements. The SAXS curve of AP205 VLP at a concentration of around 1 wt% in Figure shows the characteristic features of nano-sized particles. The overall scattering of the relatively monodisperse nanoparticle can be observed at low q values < 0.1 nm -1 , followed by a Guinier region and the characteristic maxima and minima from the form factor scattering. . (B) The pair-distance distribution function (p(r), black line), obtained from the GIFT analysis with the corresponding best possible fit from deconvolution (dashed red line). Note that r in this plot represents the characteristic distance. (C) The resulting ρ(r) assuming radial symmetry with r being the radius. The width of the second maximum was determined by the point of inflections. Residuals of the GIFT fitting and the determination of the point of inflections of ρ(r) can be found in Figure .