One-pot synthesis of gold nanostars using plant polyphenols for cancer photoacoustic imaging and photothermal therapy

Abstract

Branched plasmonic nanostructures have been found to exhibit strong enhancement of the electromagnetic field surrounding their multibranched petals. This feature endows them with improved performance in catalysis, surface-enhanced Raman scattering, photoacoustic imaging, and photothermal therapy. Albeit several synthesis techniques have been developed, the precisely controlled growth of highly branched nanostructures with a one-pot surfactant-free procedure is still challenging. Herein, we present a simple seedless route to synthesize gold nanostars (AuNSs) using a natural plant polyphenol, gallic acid (GA), as a reducing and stabilizing agent. The size and shape of AuNSs can be tuned by simply adjusting the amount of added GA. Under the optimum condition, the as-prepared AuNSs with diameters about 100 nm exhibit strong near-infrared absorption, good photothermal efficiency, and high biocompatibility. We demonstrate that AuNSs can be utilized for simultaneous photoacoustic imaging and photothermal therapy in living cancer cells. This study highlights facile synthesized AuNSs could serve as a promising platform for cancer diagnosis and therapy.

Design and synthesis of gold nanostars-based SERS nanotags for bioimaging applications

“…A seedless synthesis of nanostars that employed glucosamine or glucamine without any additional surfactants or shape-directing agents was reported by Moukarzel et al, (Figure 5b) [70]. Similarly, homogeneous nanostars were produced by using gallic acid (Figure 5c) [71]. Kircher et al developed a seed-mediated method to produce various shapes of nanoparticles using only alkaline hydrogen peroxide and gold chloride, demonstrating the capability to controllably generate various shapes and sizes of nanostars by closely tuning the reaction kinetics (Figure 5d) [72].…”

“…Copyright 2011 American Chemical Society; (b) glucosamine, adapted from ref [70]. with permission from The Royal Society of Chemistry; (c) gallic acid[71], (d) hydrogen peroxide, adapted with permission from ref [72],. Copyright 2017 WILEY-VCH; (e) dopamine, adapted from ref [73].…”

Near-Infrared Photoactive Theragnostic Gold Nanoflowers for Photoacoustic Imaging and Hyperthermia

“…The latter has been confirmed by several studies that validate their application for tumor hyperthermia, with therapeutic responses for a laser power density of 0.2 W/cm 2 , the lowest reported pulsed lasers intensities (PW) . In addition, their use as active agents for photothermia has been reported, which combined with the surface-enhanced Raman spectroscopy (SERS) techniques and photoacoustic images, have allowed therapy and imaging to be carried out simultaneously. , With such a variety of geometries and sizes, the choice of nanostructures and their synthesis and modifications are fundamental in the development of nanostructures for medical applications …”

“…17 In addition, their use as active agents for photothermia has been reported, which combined with the surface-enhanced Raman spectroscopy (SERS) techniques and photoacoustic images, have allowed therapy and imaging to be carried out simultaneously. 18,19 With such a variety of geometries and sizes, the choice of nanostructures and their synthesis and modifications are fundamental in the development of nanostructures for medical applications. 20 Herein, we report the synthesis and biomedical applications of a theragnostic Au-based NPs with absorption in the NIR.…”

Engineering Plasmonic Nanoparticles for Enhanced Photoacoustic Imaging

“…Gold nanoparticles are the most commonly used plasmonic PA contrast agents . They can be synthesized as spheres, cubes, plates, rods, ,,− cages, − shells, bipyramids, and stars. , The tips and edges lead to enhancement of the electromagnetic field as electron density increases at the tips. Simulations have shown that sharper tips have a higher μ a compared to rounded tips .…”