Schematic representation of the DCS measurements of bare and coated AuNPs. As described in Eqs. (1)–(3), the NP sedimentation time under a centrifugal force is directly correlated to their effective density. In the case of a bare AuNP, the effective density ρeff is close to the theoretical value (i.e. 19.3 g cm−3) while for a polymer coated AuNP, the effective density is affected (as described in the Eq. (3)) and also the sedimentation time. Scheme drawn with Adobe Photoshop.