Gold Nanoprisms as Optoacoustic Signal Nanoamplifiers for In Vivo Bioimaging of Gastrointestinal Cancers

Abstract

Early detection of cancer greatly increases the chances of a simpler and more effective treatment. Traditional imaging techniques are often limited by shallow penetration, low sensitivity, low specificity, poor spatial resolution or the use of ionizing radiation. Hybrid modalities, like optoacoustic imaging, an emerging molecular imaging modality, contribute to improving most of these limitations. However, this imaging method is hindered by relatively low signal contrast. Here, gold nanoprisms (AuNPrs) are used as signal amplifiers in multispectral optoacoustic tomography (MSOT) to visualize gastrointestinal cancer. PEGylated AuNPrs are successfully internalized by HT-29 gastrointestinal cancer cells in vitro. Moreover, the particles show good biocompatibility and exhibit a surface plasmon band centered at 830 nm, a suitable wavelength for optoacoustic imaging purposes. These findings extend well to an in vivo setting, in which mice are injected with PEGylated AuNPrs in order to visualize tumor angiogenesis in gastrointestinal cancer cells. Overall, both our in vitro and in vivo results show that PEGylated AuNPrs have the capacity to penetrate tumors and provide a high-resolution signal amplifier for optoacoustic imaging. The combination of PEGylated AuNPrs and MSOT represents a significant advance for the in vivo imaging of cancers.

Gold nanoprisms as a hybrid in vivo cancer theranostic platform for in situ photoacoustic imaging, angiography, and localized hyperthermia

“…The surfactant-free methods for synthesis and characterization of functionalized PEGylated AuNprs can be found in our previous publications [7,9]. Briefly, before functionalization, AuNprs were washed in deionized (DI) water and suspended in 2-(morpholino)ethanesulfonic acid (MES; 0.1 M, pH 6.0) solution.…”

“…More recently, Bao et al reported the use of AuNprs as a novel contrast agent for the hybrid technique of photoacoustic imaging (PAI). The authors demonstrated an in silico electron tomographic reconstruction of such Au nanostructures, which showed promise for application in biomedical imaging, drug delivery, and photothermal therapy [9].…”

Investigating the Role of Shape on the Biological Impact of Gold Nanoparticles in Vitro

“…Due to their plasmonic properties, gold nanoparticles (GNPs) have been proposed as advantageous nano-sized materials for use in the various diagnostic and therapeutic applications, such as cell imaging, targeted drug delivery, thermal ablation, phototherapy [1][2][3][4][5][6][7].. To date spherical GNPs have been proven as one of the most biocompatible NP models for biological-based applications [8][9][10][11][12]. Recently, it has been reported that the specific shape of GNPs can be exploited to advantageously tune these nanomaterials for any biomedical application of choice [8,13].…”

“…Recently, it has been reported that the specific shape of GNPs can be exploited to advantageously tune these nanomaterials for any biomedical application of choice [8,13]. Examples of such alternatively shaped GNPs being produced include, amongst others, rods, triangles, hexagons, prisms, urchins, cubes and wires [11,14].…”

“…Examples of such alternatively shaped GNPs being produced include, amongst others, rods, triangles, hexagons, prisms, urchins, cubes and wires [11,14]. Triangular and hexagonal GNPs have been specifically reported as promising contrast agents for in vivo imaging applications in place of the commonly used spherical GNPs [8,13,15]. The reason for this is due to the shift of the optical resonance of these differently shaped GNPs to the near-infrared region of the spectrum, which allows for a greater potential to penetrate deeper inside tissues without photobleaching [5,13,16].…”