Amplified Photoacoustic Performance and Enhanced Photothermal Stability of Reduced Graphene Oxide Coated Gold Nanorods for Sensitive Photoacoustic Imaging

Abstract

We report a strongly amplified photoacoustic (PA) performance of the new functional hybrid material composed of reduced graphene oxide and gold nanorods. Due to the excellent NIR light absorption properties of the reduced graphene oxide coated gold nanorods (r-GO-AuNRs) and highly efficient heat transfer process through the reduced graphene oxide layer, r-GO-AuNRs exhibit excellent photothermal stability and significantly higher photoacoustic amplitudes than those of bare-AuNRs, nonreduced graphene oxide coated AuNRs (GO-AuNRs), or silica-coated AuNR, as demonstrated in both in vitro and in vivo systems. The linear response of PA amplitude from reduced state controlled GO on AuNR indicates the critical role of GO for a strong photothermal effect of r-GO-AuNRs. Theoretical studies with finite-element-method lab-based simulation reveal that a 4 times higher magnitude of the enhanced electromagnetic field around r-GO-AuNRs can be generated compared with bare AuNRs or GO-AuNRs. Furthermore, the r-GO-AuNRs are expected to be a promising deep-tissue imaging probe because of extraordinarily high PA amplitudes in the 4-11 MHz operating frequency of an ultrasound transducer. Therefore, the r-GO-AuNRs can be a useful imaging probe for highly sensitive photoacoustic images and NIR sensitive therapeutics based on a strong photothermal effect.

Two-dimensional non-carbonaceous materials-enabled efficient photothermal cancer therapy

“…New 2D nanosystems with more biocompatible compositions and nanostructures are to be explored to promote the clinical translation of 2D nanosystems. In addition, the multifunctional and hybridized strategies should be further optimized to endow these 2D nanosystems with more specific functionalities, not just restricted to conventional MR, CT and PA imaging [187,188]. Other advanced imaging modalities can be integrated into these 2D nanosystems.…”

Recent Advances in Photoacoustic Imaging for Deep-Tissue Biomedical Applications

“…Various nanocomposites have been developed for the amplification of PA signals, such as dye-graphene 133, gold-graphene 134, 135. The PA signal amplification mechanisms of these nanocomposites mainly include absorption superposition 136, interaction of different agents 137 and reduced heat transfer resistance 135. For example, Gambhir et al developed a family of composites based on single-walled carbon nanotubes (SWNTs) and organic dyes for highly sensitive PAI 136, 138.…”

“…Thus the ICG-coated SWNTs showed higher PA contrast and can easily detect ∼20 times fewer cancer cells. Lim and co-workers reported a hybrid PA contrast agent (rGO-AuNR), composed of gold nanorods and reduced graphene oxide (rGO), for sensitive PAI 135. GO-coated gold nanorods (GO-AuNRs) were prepared through simple electrostatic interactions.…”

Development of graphene oxide-wrapped gold nanorods as robust nanoplatform for ultrafast near-infrared SERS bioimaging

“…[17][18][19][20] GO-wrapped metal nanomaterials for SERS bioimaging by using the intrinsic Raman signals of GO (D and G bands) have also been developed in the recent years. [21][22][23] However, this type of SERS probe with fixed pattern is limited for the multi-color Raman bioimaging.…”

“…Gold nanorods (GNRs), a typical gold nanostructure, have received significant attention in the fields of material and life sciences due to their high extinction coefficient of longitudinal surface plasmon (LSPR) in the NIR region. 19 Interestingly, the negative charge on the GO sheet surface enables utilization in the surface modification of positive-charged GNRs. 24,25 Recently, GO-encapsulated GNRs have been applied to load anticancer agents for drug delivery, owing to the strong adsorption of aromatic molecules on graphene sheet.…”