Table 1.

Physicochemical characterisation of the 50 nm and 150 nm SiO₂-NPs in different media. Nanoparticle dispersion (100 µg/mL) in water, serum free HBSS and HBSS supplemented with 10% foetal bovine serum (FBS) were characterised by differential centrifugal sedimentation (DCS) and dynamic light scattering (DLS) as described in the Experimental section. The table shows the apparent diameter and peak full width at half maximum (FWHM) obtained by DCS, together with the results obtained by cumulant analysis of the DLS data (z-average diameter and polydispersity index, PDI). The corresponding distributions are shown in Supporting Information File 1, Figures S2 and S3. For DLS results, errors represent standard deviation of 4 replicates (11 runs each).

Nanoparticle	Medium	DCS apparent diameter (nm)	DCS FWHM (nm)	Diameter (z-average, nm)	PDI
50 nm SiO2	water	41	20	76a	0.159a
	HBSS	44	23	79 ± 1b	0.17 ± 0.02b
	HBSS, 10% FBS	50	27	102 ± 3c	0.42 ± 0.07c
150 nm SiO2	water	160, 183d	60d	154 ± 4	0.03 ± 0.03
	HBSS	159, 181d	60d	190 ± 2	0.02 ± 0.01
	HBSS, 10% FBS	149, 170d	60d	209 ± 2	0.18 ± 0.02

^aData (for equivalent batch) reproduced from [42]. ^bThe presence of larger particles in the distribution of sizes (see DCS data in Supporting Information File 1, Figure S3) will bias the DLS average towards larger sizes due to the stronger scattering from larger particles (the scattering intensity grows strongly with particle size). ^cA second small peak around 10 nm due to the presence of proteins was also visible (Supporting Information File 1, Figure S2) which explains the high average diameter and PDI. This was not visible for the larger particles, likely due to the substantially stronger scattering stemming from them. ^dMultiple peaks were observed by DCS (Supporting Information File 1, Figure S3) and both peak positions are reported together with the combined width.