Mechanisms of Radical Formation on Chemically Modified Graphene Oxide under Near Infrared Irradiation

Abstract

Carbon-based nanomaterials exist in different forms, and the key which links all these nanomaterials lies in the high percentage of carbon atoms connected through sp 2 or sp 3 bonds. The small size and the different properties of these materials stir a strong interest in different application fields from electronics to biomedicine. Especially, carbon-based nanomaterials have received a growing interest due to their interaction with light. [1] This property can be exploited in a wide variety of applications, including phototherapy. The therapeutic benefit of phototherapy lies on an easy and flexible control of the light irradiation, the possibility to treat specific localized areas, as well as control time and dose of the therapeutic action. [2] Depending on their interaction with light, two classes of phototherapies can operate. The first is the photothermal therapy (PTT), which consists of the conversion of the adsorbed light by a material into surface vibrations producing heat. The local increase of the temperature can induce photoablation of tumor cells. [3] The second is the photodynamic therapy (PDT), where the interaction with light produces free radicals and, most importantly, reactive oxygen species (ROS). This leads to high oxidative stress that destabilizes cell machinery and induces apoptosis. [4] PDT is currently the most explored type of phototherapy for cancer treatment. Compared to PTT, PDT was already approved by FDA. [5] Within the different classes of carbon materials, graphene family nanomaterials have gained a lot of consensuses as tools in cancer therapy. They are composed of hexagonal rings of carbon with electron delocalization depending on the type of graphene material. [6] These 2D materials are good photothermal agents due to their ability to absorb at near-infrared (NIR) wavelengths. [7] Graphene generally shows poor colloidal stability, and this limits its use in drug delivery. [8] Graphene oxide (GO) is the oxidized form of graphene. The oxidative synthesis process enriches GO surface with a wide variety of organic groups such as epoxides, hydroxyl and carboxyl groups. [8] Because of its biocompatibility, hydrophilicity, high colloidal stability, and versatile surface chemistry, the biomedical applications of GO have been widely explored. In addition, GO can be easily

Solar-powered simultaneous highly efficient seawater desalination and highly specific target extraction with smart DNA hydrogels

“…GDH exhibited outstanding antibiofouling activity upon the visible light irradiation using Staphylococcus aureus and Escherichia coli as the test bacteria (fig. S12), which can be attributed to the production of oxygen toxic species by the incorporated GO with photocatalytic activity ( 62 , 63 ). Moreover, the bacteria in seawater had no obvious effect on uranium adsorption upon the application of the platform in the extraction of 8-ppm uranyl-containing natural seawater, with a uranyl-containing sterile water sample as control (fig.…”

“…The final concentration was 100 times of that in natural seawater. Coexisting ions in simulated mine water samples including 173 ppm of Mn 2+ , 158 ppm of Ca 2+ , 9 ppm of Mg 2+ , 170 ppm of Al 3+ , 41 ppm of Zn 2+ , and 180 ppm of Fe 2+ ( 63 ). Other major ions such as Na + , Mg 2+ , Ca 2+ , and K + were kept at their original natural concentrations.…”

Environmental and Health Impacts of Graphene and Other Two-Dimensional Materials: A Graphene Flagship Perspective

“…78 These moieties changed the chemical structure of GO and likely reduced the cytotoxic effects of the abundant oxygenated groups as GO contains a basal level of stabilized radicals responsible for triggering cellular toxicity; indeed, it is notable that GO may cause the depletion of glutathione (GSH), the main antioxidant molecule in the cell, thus evoking oxidative stress in cells. 79,80 Moreover, if further functionalities are able accelerate the catalytic activity of the enzymes involved in the degradation of GO, then the degradation could also consequently be enhanced. 26 Changes in superoxide dismutase (SOD) and lipid peroxidation (LPO) of Daphnia suggested elevated GOmediated oxidative stress and damages.…”

“…The authors used a GO modified by linking chloroacetic acid to the hydroxyl groups, imidazole to the carboxylic groups, or diaminotriethylene glycol to the epoxides . These moieties changed the chemical structure of GO and likely reduced the cytotoxic effects of the abundant oxygenated groups as GO contains a basal level of stabilized radicals responsible for triggering cellular toxicity; indeed, it is notable that GO may cause the depletion of glutathione (GSH), the main antioxidant molecule in the cell, thus evoking oxidative stress in cells. , Moreover, if further functionalities are able accelerate the catalytic activity of the enzymes involved in the degradation of GO, then the degradation could also consequently be enhanced …”

Slow and steady wins the race: Fractionated near-infrared treatment empowered by graphene-enhanced 3D scaffolds for precision oncology

“…GO is a well-known photosensitizing agent, that can absorb near-infrared (NIR) light and convert it efficiently into heat [ [14] , [15] , [16] ]. Moreover, GO demonstrates excellent capability to generate reactive oxygen species (ROS) upon light irradiation, promoting selective destruction of tumor cells while minimizing damage to healthy tissues [ [17] , [18] , [19] , [20] ]. In combination with biocompatible polymers, such as poly(lactic-co-glycolic acid) (PLGA), GO can be used to create 3D printed scaffolds, offering a powerful platform for both cancer treatment and, at the same time, tissue regeneration [ 21 , 22 ].…”