Synergistic Reducing Effect for Synthesis of Well-Defined Au Nanooctopods With Ultra-Narrow Plasmon Band Width and High Photothermal Conversion Efficiency

Abstract

Branched Au nanoparticles have attracted intense interest owing to their remarkable properties and a wide variety of potential applications in surface-enhanced Raman spectroscopy (SERS), photothermal therapy, photoacoustic imaging, and biomedicines. The morphology and spatial arrangement of branches play the most crucial role in the determination of their properties and applications. However, it is still a synthetic challenge to control the exact arm numbers of branches with specific spatial arrangements. Here we report a facile method for the kinetically controlled growth of Au nanooctopods (NOPs) with a high yield (81%), monodispersity, and reproducibility by using the synergistic reducing effect of ascorbic acid and 1-methylpyrrolidine. The NOPs have eight arms elongated along <111> directions with uniform arm lengths. Due to their well-defined size and shape, NOPs show ultra-narrow surface plasmon band width with a full width at half maximum of only 76 nm (0.20 eV). Upon irradiation with laser, the NOPs possessed excellent photothermal conversion efficiencies up to 83.0% and photoacoustic imaging properties. This work highlights the future prospects of using NOPs with desired physicochemical properties for biomedical applications.

Gold Nanotetrapods with Unique Topological Structure and Ultranarrow Plasmonic Band as Multifunctional Therapeutic Agents

“…To further increase V dep , we replaced HMT with 1-methylpyrrolidine, which can reduce HAuCl 4 to Au 0 with a much faster rate (Figure S13). Interestingly, instead of NTPs, single-crystalline Au nanooctopods with eight arms were obtained in our previous work . The HRTEM image of nanooctopods shows the eight arms toward the ⟨111⟩ directions (Figure S14), which is in agreement with the condition for V dep ≫ V diff of the growth mechanism (Scheme c).…”

Gold Nanoparticle Enantiomers and Their Chiral-Morphology Dependence of Cellular Uptake

“…The chiral Au NOPs were prepared by the regrowth of single-crystalline Au NOP seeds synthesized with a method previously reported (Supporting Information Figure S1). 46,47 In a typical synthesis of chiral NOPs, the regrowth of NOP seeds was achieved by reducing HAuCl 4 through a mixture of coreducing agents, that is, 1-MP and AA in a CTAB aqueous solution. GSH was used as a chiral additive for the regrowth of NOP seeds to chiral NOPs.…”

Tuning the Chiral Morphology of Gold Nanoparticles with Oligomeric Gold–Glutathione Complexes

“…The chiral Au NPs were synthesized by the regrowth of Au NOPs reported previously by our group (Figure S1). 41 In the regrowth progress, the GSH was used as a chiral additive to control the chiral morphology of Au NPs. To our surprise, the incubation time of the GSH aqueous solution (10.0 mM) at 30 °C greatly affected the morphology of the Au NPs.…”