Pro- and anti-oxidant properties of near-infrared (NIR) light responsive carbon nanoparticles

Abstract

Elemental carbon nanomaterials (ECNMs) are redox active agents that can be exploited to purposely modify the redox balance of cells. Both pro-or antioxidant properties have been reported. However, to the best of our knowledge, there are not comprehensive studies exploring both properties on the same material in view of a potential application in medicine. At the same time, the effect of the bulk structure on the pro/antioxidant properties is poorly known. Here, carbon nanoparticles (CNPs) derived by glucose with definite size and shape have been prepared, and their redox properties evaluated in cell free systems in the dark or following activation with a Near Infrared (NIR) laser beam (945 nm, 1.3 W/cm 2 ). We found that, when irradiated with NIR, CNPs efficiently generate heat and singlet oxygen ( 1 O2), a property that can be exploited for dual photo-thermal (PT)/ photodynamic (PD) therapy in cancer. On the other hand, in the absence of photo-activation, CNPs react with both oxidant (hydroxyl radicals) and antioxidant (glutathione) species. When tested on a murine macrophages cell line (RAW 264.7) CNPs were clearly antioxidant. Furthermore, albeit efficiently internalized, CNPs do not exert cytotoxic effect up to 80 µg/ml and do not exacerbate TNF-α-mediated inflammation. Overall, the results reported herein suggest that CNPs may represent a new class of safe nanomaterials with potential applications in medicine.

Precisely Tuning Photothermal and Photodynamic Effects of Polymeric Nanoparticles by Controlled Copolymerization

“…Obviously, the intensity of the peaks continuously increased when the mixture of NP IV and TEMP were irradiated under 808 nm laser, which represented the appearance of the adduct of TEMP‐ 1 O 2 , indicating the generation of singlet oxygen from the NPs IV. Furthermore, a very strong singlet peak was also observed in Figure B, which was assigned to carbon‐centered free radicals inside the NPs, consistent with the Raman spectra. Obviously, the intensity also increased along with the increase of the irradiation time.…”

Recent Developments in the Reduction of Oxidative Stress through Antioxidant Polymeric Formulations

“…Carbon nanoparticles (CNPs) derived by glucose have been also reported to have pro- or anti-oxidant properties [106]. Kokalari and colleagues demonstrated that when irradiated with a near-infrared (NIR) laser, CNPs generate heat and singlet oxygen ( 1 O 2 ), which is useful for dual photothermal (PT)/photodynamic (PD) therapy in cancer treatment [107]. On the other hand, CNPs react with both oxidant (hydroxyl radicals) and antioxidant (glutathione) species when not photoactivated in a cell-free system.…”

Efficacy, Biocompatibility and Degradability of Carbon Nanoparticles for Photothermal Therapy of Lung Cancer

“…CNPs were obtained by hydrothermal carbonization following a previously optimized protocol [18], without modifications. Briefly, 2 g of glucose were dissolved in 50 ml of ultrapure water and subsequently 15 mg of sodium polyacrylate were added.…”

“…One aliquot of the suspension was stored at 4 • C and used as a control for comparison with the sterilized sample in terms of hydrodynamic diameter, ζ-potential (using Zetasizer Nano, Malvern Instruments, Malvern, UK) and pH. Samples were also subjected to thermogravimetric analysis, as previously described [18], to detect changes in internal structure due to the high temperature during sterilization. Sterilization was further confirmed by the absence of bacterial contamination in the agar plate test based on a protocol developed by the European Nanomedicine Characterization Laboratory [24].…”

“…CNPs exhibit photoacoustic and photothermal properties when irradiated by near infrared (NIR) light [22]. We recently reported the synthesis of tailored glucose-derived graphitic CNPs with a diameter of 80 nm that possess the ability to generate singlet oxygen and heat upon NIR irradiation in cell-free tests [18]. These CNPs were shown to be noncytotoxic toward a murine macrophage cell line and significant antioxidant activity was observed, as a consequence of their ability to scavenge hydroxyl radicals.…”