Graphene quantum dots as autophagy-inducing photodynamic agents

Abstract The excellent photoluminescent properties of graphene quantum dots (GQD) makes them suitable candidates for biomedical applications, but their cytotoxicity has not been extensively studied. Here we show that electrochemically produced GQD irradiated with blue light (470 nm, 1 W) generate re...

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Bibliographic Details
Published in:Biomaterials 2012-10, Vol.33 (29), p.7084-7092
Main Authors: Markovic, Zoran M, Ristic, Biljana Z, Arsikin, Katarina M, Klisic, Djordje G, Harhaji-Trajkovic, Ljubica M, Todorovic-Markovic, Biljana M, Kepic, Dejan P, Kravic-Stevovic, Tamara K, Jovanovic, Svetlana P, Milenkovic, Marina M, Milivojevic, Dusan D, Bumbasirevic, Vladimir Z, Dramicanin, Miroslav D, Trajkovic, Vladimir S
Format: Article
Language:English
Subjects:
Advanced Basic Science
Apoptosis
Autophagy
Carbon
Caspases - metabolism
Cell Line, Tumor
Cell Survival
Cytotoxicity
Dentistry
DNA Fragmentation
Dose-Response Relationship, Drug
Electrochemistry - methods
Enzyme Activation
Flow Cytometry - methods
Graphite - chemistry
Humans
Luminescence
Microscopy, Electron, Transmission - methods
Nanoparticle
Oxidative Stress
Oxygen - chemistry
Photosensitisation
Photosensitizing Agents - pharmacology
Quantum Dots
RNA Interference
Time Factors
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Summary:Abstract The excellent photoluminescent properties of graphene quantum dots (GQD) makes them suitable candidates for biomedical applications, but their cytotoxicity has not been extensively studied. Here we show that electrochemically produced GQD irradiated with blue light (470 nm, 1 W) generate reactive oxygen species, including singlet oxygen, and kill U251 human glioma cells by causing oxidative stress. The cell death induced by photoexcited GQD displayed morphological and/or biochemical characteristics of both apoptosis (phosphatidylserine externalization, caspase activation, DNA fragmentation) and autophagy (formation of autophagic vesicles, LC3-I/LC3-II conversion, degradation of autophagic target p62). Moreover, a genetic inactivation of autophagy-essential LC3B protein partly abrogated the photodynamic cytotoxicity of GQD. These data indicate potential usefulness of GQD in photodynamic therapy, but also raise concerns about their possible toxicity.
ISSN:0142-9612
1878-5905
DOI:10.1016/j.biomaterials.2012.06.060