Dynamic light scattering for gold nanorod size characterization and study of nanorod–protein interactions

Abstract

In recent years, there has been considerable interest and research activity in using gold nanoparticle materials for biomedical applications including biomolecular detection, bioimaging, drug delivery, and photothermal therapy. In order to apply gold nanoparticles in the real biological world, we need to have a better understanding of the potential interactions between gold nanoparticle materials and biomolecules in vivo and in vitro. Here, we report the use of dynamic light scattering (DLS) for gold nanorods characterization and nanorod-protein interaction study. In the size distribution diagram, gold nanorods with certain aspect ratios exhibit two size distribution peaks, one with an average hydrodynamic diameter at 5-7 nm, and one at 70-80 nm. The small size peak is attributed to the rotational diffusion of the nanorods instead of an actual dimension of the nanorods. When proteins are adsorbed to the gold nanorods, the average particle size of the nanorods increases and the rotational diffusion-related size distribution peak also changes dramatically. We examined the interaction between four different proteins, bovine serum albumin, human serum albumin, immunoglobulin G, and immunoglobulin A (IgA) with four gold nanorods that have the same diameter but different aspect ratios. From this study, we found that protein adsorption to gold nanorods is strongly dependent on the aspect ratio of the nanorods, and varies significantly from protein to protein. The two serum albumin proteins caused nanorod aggregation upon interaction with the nanorods, while the two immunoglobulin proteins formed a stable protein corona on the nanorod surface without causing significant nanorod aggregation. This study demonstrates that DLS is a valuable tool for nanorod characterization. It reveals information complementary to molecular spectroscopic techniques on gold nanorod-protein interactions.

Systematic in vitro toxicological screening of gold nanoparticles designed for nanomedicine applications

“…12 Also, the anisotrophy of nanorods means that their DLS measurments cannot not be considered as their true physical dimensions. 35 …”

High aspect ratio gold nanorods displayed augmented cellular internalization and surface chemistry mediated cytotoxicity

“…Nano-gold in particular is well renowned for displaying a high extent of particle association in cell culture medium due to the increased ionic strength which induces strong hydrostatic interactions between gold particles [28,29]. As such, dynamic light scattering (DLS) assessment was performed in both water and cell culture medium to ascertain how the GNRs behaved in a fluid suspension (Table 1), as monitored through their effective hydrodynamic diameters [30]. Numerous conclusions can be drawn from these DLS results.…”

Plasmonic nanoparticles and their characterization in physiological fluids

“…Charge-dependent interactions with proteins and cells Kittler (2010) [65] Ag NPs (PVP or citrate coated) Complete cell media Effect of proteins on dispersability and biological activity of NPs Lankoff (2012) [66] Ag NPs Complete cell media (5% FBS) Impact of aggregation on cellular response Li (2015) [67] Cu NPs Complete cell media Dissolution of NPs in cell culture media Liu (2012) [68] Au nanorods (CTAB coated) BSA, HSA, IgG Interaction with proteins McCuspie (2011) [69] Ag NPs (BSA coated) Synthetic lung fluid Dispersion stabilization of NPs and effect on colloidal stability Mahl (2010) [70] Au NPs (TPPTS and PVP coated) Complete cell media (FBS up to 10%) Stability and aggregation; Impact on cellular response Montes-Burgos (2010) [71] Au NPs Human blood plasma Protein adsorption and stability Moyano (2014) [72] Au NPs (sulfobetain headgroups) Diluted human serum Synthesis of corona-free NPs Mukherjee (2014) [73] Ag NPs Complete cell media Impact of physiological interactions on cellular dosimetry Murdock (2008) [13] Cu and Ag NPs Complete cell media Characterization of NP dispersion in cell media Pal (2014) [74] Ni NPs Complete cell media Characterization of NP dispersion in complex media and dosimetry Pyshnaya (2014) [75] Au nanorods and spheres (PEI and BSA coated)…”

“…It has been repeatedly shown that the degree of aggregation has an impact on cellular response [70,77] and much effort is dedicated to improve the stability of NPs in such media [76]. Although it has been demonstrated that protein adsorption can generally stabilize the system [62,68,71], surface-charge dependent interactions must be also considered [64]; characterizing the extent and time evolution of protein adsorption may bring further insights [60,72]. Other studies have used the method to study kinetics of aggregation and dissolution of e.g.…”