Fig. 5
Physicochemical characterization of gold nanoparticles after protein corona formation. (a) Dynamic light scattering (DLS) results show an average hydrodynamic diameter of 28.8 ± 5.18 nm, indicating an increase in size following protein corona formation. (b) Zeta potential measurements show a shift from approximately − 20 mV to − 0.75 mV, suggesting the replacement or masking of the negatively charged citrate ions by protein adsorption. (c) UV–Vis spectroscopy indicates a redshift of the surface plasmon resonance peak from 520 nm to 523 nm after protein corona formation, confirming changes in the nanoparticle surface environment. (d) Transmission electron microscopy (TEM) image displays a visible protein halo surrounding the gold nanoparticles. The corona thickness was measured to be approximately 2.46 nm using ImageJ software. The average particle size, based on TEM analysis, was found to be 28.3 ± 1.8 nm, which also confirms an increase from the initial core size of ~ 22 nm.
