Enhanced Photothermal and Photoacoustic Performance of Graphene Oxide in NIR-II Biowindow by Chemical Reduction

We report on a novel strategy for constructing graphene oxide nanomaterials with strongly enhanced photothermal (PT) and photoacoustic (PA) performance in the near-infrared (NIR)-II biowindow by chemical reduction. Optical spectra clearly reveal that obvious enhancement of optical absorption is observed in the whole NIR wideband from the NIR-I to NIR-II region for chemically reduced graphene oxide (CR-G) nanomaterials, which is mainly arising from the restoration of the electronic conjugation within the graphene oxide sheets and therefore inducing a black-body re-introduction effect of typical graphite-like materials. We experimentally synthesized CR-G samples with different degrees of reduction to demonstrate the efficiency of the proposed strategy. Experimental results show that the PT performance of the CR-G samples is greatly improved owing to the absorption enhancement by chemical reduction in the NIR-II biowindow. Furthermore, both in vitro and in vivo PA imaging of the CR-G samples with different degrees of reduction are performed to demonstrate their enhanced NIR-II PA performances. This work provides a feasible guidance for the rational design of graphene oxide nanomaterials with great potential for PT and PA applications in the NIR-II biowindow by chemical reduction.

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

Oxygen content-related DNA damage of graphene oxide on human retinal pigment epithelium cells

Arguments regarding the biocompatibility of graphene-based materials (GBMs) have never ceased. Particularly, the genotoxicity (e.g., DNA damage) of GBMs has been considered the greatest risk to healthy cells. Detailed genotoxicity studies of GBMs are necessary and essential. Herein, we present our recent studies on the genotoxicity of most widely used GBMs such as graphene oxide (GO) and the chemically reduced graphene oxide (RGO) toward human retinal pigment epithelium (RPE) cells. The genotoxicity of GO and RGOs against ARPE-19 (a typical RPE cell line) cells was investigated using the alkaline comet assay, the expression level of phosphorylated p53 determined via Western blots, and the release level of reactive oxygen species (ROS). Our results suggested that both GO and RGOs induced ROS-dependent DNA damage. However, the DNA damage was enhanced following the reduction of the saturated C–O bonds in GO, suggesting that surface oxygen-containing groups played essential roles in the reduced genotoxicity of graphene and had the potential possibility to reduce the toxicity of GBMs via chemical modification.

Paper-based potentiometric sensing devices modified with chemically reduced graphene oxide (CRGO) for trace level determination of pholcodine (opiate derivative drug)

Robust, reliable and cost-effective paper-based analytical device for potentiometric pholcodine (opiate derivative drug) ion sensing has been prepared and characterized.

Complex Permittivity and Electromagnetic Interference Shielding Effectiveness of OPEFB Fiber-Polylactic Acid Filled with Reduced Graphene Oxide

This study was aimed at fabricating composites of polylactic acid (PLA) matrix-reinforced oil palm empty fruit bunch (OPEFB) fiber filled with chemically reduced graphene oxide (rGO). A total of 2–8 wt.% rGO/OPEFB/PLA composites were characterized for their complex permittivity using an open-ended coaxial probe (OEC) technique. The shielding efficiency properties were calculated using the measured transmission (S21) and the reflection (S11) coefficient results. All the measurements and calculations were performed in the 8–12 GHz frequency range. The morphological and microstructural study included X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FTIR). The results indicated that the incorporation of rGO as filler into the composites enhanced their complex permittivity properties. The composites showed a total shielding efficiency (SET) of about 31.2 dB at a frequency range of 8–12 GHz, which suggests their usefulness for microwave absorption.