The aim of this study is to compare the optical
scattering properties of different gold nanoparticles (GNPs),
with different shapes (spherical, GNSs, and flower-shaped,
GNFs), sizes (20, 30, and 50 nm), and surface chemistries (with
and without PEG). These scattering properties give geometrical
characterization of hydrodynamic sizes of GNPs by using the
scattering correlation spectroscopy. Afterward, a multiparametric
comparative study of the scattering efficiency is presented
depending on various parameters such as GNPs geometry,
excitation wavelength (532 and 633 nm) and powers (from 5 to
100 μW). As predicted by Mie theory, we demonstrate that the
increase in GNSs size leads to an increase of the scattered
intensity, proportional to the excitation power. The scattered
signal is the highest when the excitation wavelength is closer to
the localized surface plasmon resonance. In the case of GNFs, the measured scattered signal is around 1000 times stronger than
that for GNSs of the same size and concentration. For GNFs, a scattering coefficient at the plasmon resonance of around 2 ×
10−13 m2 was calculated, which is comparable to the scattering coefficient of a GNS with a diameter of 300 nm. Due to their
strong scattering properties, GNFs appear as a good alternative to GNSs of the same size for cell imaging.