Shape-Templated Growth of Au@Cu Nanoparticles

Abstract

We report the formation of copper nanoparticles with various morphologies and low polydispersity, using Au nanoparticles as templates. This seeded growth strategy is based on the reduction of Cu2+ with hydrazine in water at low temperature. Additionally, the use of poly(acrylic acid) as capping agent allows synthesis under aerobic conditions. The dimensions of the resulting Au@Cu nanoparticles can be readily tuned through either the dimensions of the Au cores or the Cu/Au molar ratio. Although Au and Cu show a significant lattice mismatch, epitaxial growth of Cu onto single crystal Au nanorods was confirmed through high-resolution electron microscopy and electron diffraction analysis. The effects of core morphology on the optical properties of the core–shell nanoparticles were analyzed by vis-NIR spectroscopy and were found to agree with simulations based on the boundary element method. This work contributes to understand the strong effect of interband transitions on the optical response of Au@Cu and to confirm the importance of tuning the localized surface plasmon resonance away from the interband transitions.

Bimetallic Nanoparticles: Enhanced Magnetic and Optical Properties for Emerging Biological Applications

“…Sensing LSPR shift AuAg [163] Surface-enhanced Raman scattering (SERS) AuAg [76] AuAg [166] GMR sensor; competition assay FeCo [112,113,187] Magnetic capture FePt [171] Magnetically-enhanced colorimetric biosensing PtCo [117] QCM with magnetically controlled permeability AuCo [80] Electrochemical biosensor PtPd [96] Imaging An imaging probe screening with dual energy mammography or computed tomography AuAg [71] The optical absorption cross sections AuAg [72] MRI contrast agent (no imaging) FePt [103] MRI in vitro FePt [105] FeNi [115] PtCo [40] MRI in vivo AuCu [84] FeCo [110] FePt [177] Dual modal CT/MRI molecular imaging in vitro and in vivo FePt [132] MRI and near-infrared agents FeCo [111] Multimodal imaging − Computed tomography (CT), − Magnetic resonance imaging (MRI), − Photoacoustic (PA) imaging, − High-order multiphoton luminescence (HOMPL) microscopy FePt [102] in vivo Multimodal SERS-MRI-CT imaging AuFe [79] in vivo NIR thermal imaging and photoacoustic imaging AuPt [95] Thermal treatment in vitro hyperthermia FePt [109] Photothermal FePt [104] Hyperthermia CuNi [119,188] Tumor chemo-photothermal therapy AuPt [95]…”

Space‐Confined Seeded Growth of Cu Nanorods with Strong Surface Plasmon Resonance for Photothermal Actuation

“…The weak plasmon resonance of Cu is caused by its overlap with the interband transitions (ca. 2.1 eV) that can be excited by light with a wavelength shorter than 590 nm . The simultaneous interband transitions significantly dampen the plasmon resonance, which occurs at circa 570 nm for spherical Cu nanoparticles.…”

Targeted 64Cu‐labeled gold nanoparticles for dual imaging with positron emission tomography and optical imaging

“…An interesting alternative pathway to create 64 Culabeled AuNPs was described recently and is based on the direct radiolabeling of AuNPs with [ 64 Cu]Cu(0) by either synthesizing the AuNPs together with 64 CuCl 2 directly in solution 23,29 or by reduction of [ 64 Cu]Cu 2+ onto the surface of the AuNPs. 41,42 Thus, we intended to explore the potential of this 64 Cu-radiolabeling route for our AuNPs and to comparatively assess the stability of the radiolabel introduction compared with the conventional chelator-based approach. 41 The directly radiolabeled AuNPs [ 64 Cu]Cu-3 could obtain, under identical conditions, RCPs of more than 99% and RCYs of 69 ± 7% (d.c.).…”