Efficient Near-IR Hyperthermia and Intense Nonlinear Optical Imaging Contrast on the Gold Nanorod-in-Shell Nanostructures

Abstract

New gold nanorod (Au NR)-in-shell nanostructures were developed to be more efficacious than Au NRs in near-IR (NIR) hyperthermia and nonlinear optical imaging contrast. Au NR-in-shell nanostructures are composed of an intact Au NR in a Au/Ag nanoshell. These nanostructures have a broad, intense absorption band that extends from 400 nm to 900 nm in the NIR. They are more efficient and efficacious than Au NRs with respect to in vitro hypothermia performance. Au NR-in-shell-labeled cancer cells were destroyed using continuous-wave NIR radiation with 50% less laser power than needed for Au NRs. Noticeably, the area of the destroyed cells was significantly larger than the size of the laser irradiation beam; in contrast, the destroyed area was usually restricted to the size of the laser beam spot when Au NRs were used. With their extraordinarily broad and strong surface plasmon resonance band, Au NR-in-shell nanostructures efficiently augmented several multiphoton nonlinear processes as well. The multiphoton emission spectrum covered almost the entire visible wavelength. The yield of the multiphoton signals of Au NR-in-shell nanostructures was on average 55 times larger than that of Au NRs. In vitro images of cancer cells targeted by Au NR-in-shell nanostructures revealed a stronger multiphoton contrast than those targeted by Au NRs.

Revisiting the classification of NIR-absorbing/emitting nanomaterials for in vivo bioapplications

“…This property can be achieved by tailoring the SPR absorption band of metallic NPs by controlling the geometry or surface coating of the nanomaterials. 17,18 For the band-to-band transition, carbon-based nanomaterials have high absorption in the NIR region. 19,20 For solid-state materials doped with d-block and f-block elements, the NIR absorption (for Yb 3+ at 980 nm or Nd 3+ at~800 nm) can provide a ladder-like upconversion (UC) route for visible luminescence (most typically, 470, 650 and 800 nm for Tm 3+ and 520-540 and 650 nm for Er 3+ ) or NIR (890/1060 nm for Nd 3+ , 1470 nm for Tm 3+ , 1310 nm for Pr 3+ , 1185 nm for Ho 3+ and 1525 nm for Er 3+ ) at relatively low excitation intensity levels.…”

“…119,120 When a pulsed laser resonantly excited gold-based NPs in the SPR band, they are able to perform wavelength UC and produce intense nonlinear optical signals, such as second harmonic generation (SHG), TPF and third harmonic generation (THG). 18 Except for SPR absorption, the band-to-band transition states can also enhance the yield of nonlinear optical processes. Previous studies have shown that the electronic states of the d-sp band transition of gold have a vital role in the multiphoton excited emissions when the pulsed excitation energy matches the local field enhancement at the surface plasmon frequency.…”

Variation of Protein Corona Composition of Gold Nanoparticles Following Plasmonic Heating

“…12 Indeed, functionalized AuNRs have shown great promise in biomedical applications ranging from molecular (drug) delivery to hyperthermia cancer treatments. 20,25,26 In order to study the effect of plasmonic heating on the hard protein corona composition of AuNRs, we immersed cetyltrimethylammonium bromide (CTAB)-stabilized gold nanorods in fetal bovine serum (FBS) solutions and probed the protein corona composition at the surface of nanorods before and after plasmonic heating induced by continuous laser irradiation for various activation times. We studied the effect of plasmonic heating on AuNR−protein complexes formed at two different overall protein concentrations: 10 and 100% FBS.…”

Nanotheranostics – a review of recent publications

“…In addition, the photothermal effect induced by MMP-AuNR was able to raise the media temperature to 60°C ( Figure 1C and F), leading to the damage of tumor tissue ( Figure 1G). In a recent study carried out by Hu et al 14 the photothermal effect of AuNR was efficiently improved by a surrounding silver shell (AuNR-in-shell). The Chemotherapy X-ray imaging MR imaging [19][20][21][22][23][24][25] [27]…”