Abstract
Gold nanoprisms possess remarkable optical properties that make them useful for medical biotechnology applications such as diagnosis and photothermal therapy. However, shape-selective synthesis of gold nanoprisms is not trivial and typically requires either toxic surfactants or time-consuming purification protocols, which can limit their applicability. Here, we show how triangular gold nanoprisms of different sizes can be purified by precipitation using the non-toxic glutathione ligand, thereby removing the need for toxic surfactants and bottleneck purification techniques. The protocol is amenable for direct scaling up as no instrumentation is required in the critical purification step. The new purification method provides a two-fold increased yield in gold nanoprisms compared to electrophoretic filtration, while providing nanoprisms of similar localized surface plasmon resonance wavelength. Crucially, the gold nanoprisms isolated using this methodology show fewer non-specific interactions with cells and lower cellular internalization, which paves the way for a higher selectivity in therapeutic applications.
Highlights
Anisotropic gold nanoparticles, such as nanorods (NRs) and nanoprisms (NPrs), possess remarkable optical properties [1]
It has been reported that the as-synthesized mixture can be treated with heterobifunctional thiol containing PEG to stabilize the nanoparticles and to provide them with stealth properties
At the tested 80-mg scale, triangular NPrs could be obtained in a high yield (42 ± 7%), free of spherical gold nanoparticles and without any partition of the batch, neither during the synthesis nor in the purification step
Summary
Anisotropic gold nanoparticles, such as nanorods (NRs) and nanoprisms (NPrs), possess remarkable optical properties [1]. By altering the size and the aspect ratio of NRs and NPrs, it is possible to tune their localized surface plasmon resonance (LSPR) across the near-infrared (NIR) region of the spectrum, the range of wavelength at which the absorbance of biological tissues is highly decreased [2]. This characteristic makes them promising for biomedical applications, in both therapy and diagnosis. The superior cellular internalization of gold NPrs originates from non-specific interactions which can lead to poor cell specificity, resulting in unnecessary damage to local healthy tissue. It has been shown that usual stealth coating with poly(ethyleneglycol) (PEG) does not prevent the non-specific uptake of gold NPrs by cells [3,4,5] and no other better alternative has yet been reported for gold NPrs
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