Characterisation of PMA coated AuNPs of different sizes by TEM and DCS. Measurements for 5, 25 and 50 AuNPs are shown respectively in the top (a–d), middle (e–h) and bottom (i–l) panels. TEM measurements were performed on the polymer-coated NPs. Representative micrographs for each of the different sizes (a,e,i) and the resulting histogram counts (b,f,j) are provided with average core diameters of 4.8 ± 0.7, 26.9 ± 3.4 and 47.6 ± 5.7 nm respectively. DCS measurements were performed for the three relevant NP suspensions, i.e. AuNPs in the organic solvent (toluene) prior to PMA coating (black line), the Au-PMA polymer-coated NPs after water transfer (red line) and Au-PMA-Corona complexes in situ measured after corona formation (blue line). Representative DCS distributions are provided for each of the NP sizes (c,g,k) along with the detailed average and standard deviations across independent replicates (d,h,l). Particle diameters obtained from DCS measurements assumed a particle density of 19.3 g cm-3.