Ultrasmall Reduced Graphene Oxide with High Near-Infrared Absorbance for Photothermal Therapy

TLDR

The study develops nanosized reduced graphene oxide sheets with high NIR absorbance and biocompatibility for photothermal therapy. Nano‑rGO sheets (~20 nm) were PEGylated for stability, exhibited six‑fold higher NIR absorption than nonreduced GO, and were functionalized with an RGD peptide to enable selective uptake and effective photoablation of U87MG cells. Without NIR irradiation, nano‑rGO was non‑toxic at high concentrations, and the work demonstrates it as a cost‑effective, highly efficient photothermal agent superior to gold nanoparticles and carbon nanotubes.

Abstract

We developed nanosized, reduced graphene oxide (nano-rGO) sheets with high near-infrared (NIR) light absorbance and biocompatibility for potential photothermal therapy. The single-layered nano-rGO sheets were ∼20 nm in average lateral dimension, functionalized noncovalently by amphiphilic PEGylated polymer chains to render stability in biological solutions and exhibited 6-fold higher NIR absorption than nonreduced, covalently PEGylated nano-GO. Attaching a targeting peptide bearing the Arg-Gly-Asp (RGD) motif to nano-rGO afforded selective cellular uptake in U87MG cancer cells and highly effective photoablation of cells in vitro. In the absence of any NIR irradiation, nano-rGO exhibited little toxicity in vitro at concentrations well above the doses needed for photothermal heating. This work established nano-rGO as a novel photothermal agent due to its small size, high photothermal efficiency, and low cost as compared to other NIR photothermal agents including gold nanomaterials and carbon nanotubes.