Gold Nanostars with Reduced Fouling Facilitate Small Molecule Detection in the Presence of Protein.

Anastasiia Tukova,Alison Rodger,Inga Christine Kuschnerus,Yuling Wang,Alfonso Garcia-Bennett

doi:10.3390/nano11102565

Anastasiia Tukova, Alison Rodger + Show 3 more

Open Access

https://doi.org/10.3390/nano11102565

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Abstract

Gold nanoparticles have the potential to be used in biomedical applications from diagnostics to drug delivery. However, interactions of gold nanoparticles with different biomolecules in the cellular environment result in the formation of a “protein corona”—a layer of protein formed around a nanoparticle, which induces changes in the properties of nanoparticles. In this work we developed methods to reproducibly synthesize spheroidal and star-shaped gold nanoparticles, and carried out a physico-chemical characterization of synthesized anionic gold nanospheroids and gold nanostars through transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential (ZP), nanoparticles tracking analysis (NTA), ultraviolet-visible (UV–Vis) spectroscopy and estimates of surface-enhanced Raman spectroscopy (SERS) signal enhancement ability. We analyzed how they interact with proteins after pre-incubation with bovine serum albumin (BSA) via UV–Vis, DLS, ZP, NTA, SERS, cryogenic TEM (cryo-TEM) and circular dichroism (CD) spectroscopy. The tests demonstrated that the protein adsorption on the particles’ surfaces was different for spheroidal and star shaped particles. In our experiments, star shaped particles limited the protein corona formation at SERS “hot spots”. This benefits the small-molecule sensing of nanostars in biological media. This work adds more understanding about protein corona formation on gold nanoparticles of different shapes in biological media, and therefore guides design of particles for studies in vitro and in vivo.

Highlights

Gold nanoparticles (GNPs, used to denote any size or shape nanoparticles) are among the most widely studied nanomaterials
It should be noted that the aggregation state of the particles presented in the images (Figure 1) does not reflect their state when suspended in the solution, as measured by UV–Vis spectroscopy and dynamic light scattering (DLS)
The exciting result of this work was the discovery of reduced fouling of gold nanostars relative to spheroidal particles

Summary

Introduction

Gold nanoparticles (GNPs, used to denote any size or shape nanoparticles) are among the most widely studied nanomaterials. Since the primary report on gold colloids over 100 years ago by Faraday [1,2], extensive research has been performed on their configurations, properties, and applications. When incident light is applied to metal nanoparticles, due to the comparable size of the particles and the wavelength of the incident light, the effect of localized surface plasmon resonance (LSPR) occurs [12]. The biggest enhancements are localized in so-called “hot spots”, which have been found to occur in the areas of the highest local curvature or in the gaps between two GNPs. An LSPR “hot spot” on a particle enhances the electromagnetic field for neighboring molecules. An LSPR “hot spot” on a particle enhances the electromagnetic field for neighboring molecules This has been useful in surface-enhanced Raman spectroscopy (SERS) and surface-enhanced fluorescence (SEF) [6]

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