Toxizität von Graphenoxid: Endoperoxide als Ursache

Abstract

Potentielle biomedizinische Anwendungen von Graphenoxid (GO), z. B. als Träger von Biomolekülen, Reagentien für die photothermische Therapie oder Biosensoren, werden durch die Zytotoxizität und Mutagenität dieses Materials eingeschränkt. Es wird davon ausgegangen, dass diese Eigenschaften zumindest zum Teil auf eine von GO verursachte Erhöhung des oxidativen Stresses in Zellen zurückzuführen ist. Es ist jedoch nicht bekannt, auf welchen chemischen Fragmenten dieser ungünstige Effekt beruht. In dieser Arbeit wurden vier GOs entwickelt, welche verschiedene redoxaktive Gruppen wie Mn2+, C‐zentrierte Radikale sowie Endoperoxide (EPs) auf der Oberfläche besitzen. Der Vergleich der Fähigkeit der Materialien, reaktive Sauerstoffspezies in humanen Gebärmutterhalskrebszellen zu generieren, zeigt, dass EPs eine entscheidende Rolle im GO‐induzierten oxidativen Stress spielen. Diese Ergebnisse können für die gezielte Entwicklung von biokompatiblem und nicht‐toxischem GO für biomedizinische Anwendungen verwendet werden.

Oxo‐Functionalized Graphene as a Cell Membrane Carrier of Nucleic Acid Probes Controlled by Aging

“…D) FÀF 0 obtained for probestargetingr epresentativeR NAs in live cells and the negative control bothint he absence and presence of oxo-G 28/ 4 8C .O ther conditions are the samea si n(C). concentration of EPs (Figure 2E,F), [16] and exhibits the optimal cell membrane carrierp roperties (Figure 3C,D). In the absence of oxo-G 28d/4 8C thesep robes are strongly fluorescent (see representatived ata in Figure 3B,t he trace up to~3rd min, when the oxo-G was added).…”

“…ON1 is ak nown mixed single-stranded oligonucleotide sequence, which binds to oxo-G efficiently (Schemes 1 and 2). [16] As F we selected fluorescein, which is strongly quenched by oxo-G when placed in its proximity. [16] Surprisingly,w eo bserved that freshly prepared oxo-G (oxo-G 0 , 10 mgmL À1 )r educed the fluorescenceo ft he probe by only 2.1 fold, whereas the same material incubated in the aqueous suspension for seven days at 4 8C( oxo-G 7d/4 8C )q uenched the fluorescenceb yo ver 2.7 fold and that incubated for 28 days (oxo-G 28d/4 8C ), by 29 fold.…”

“…The formation of graphene-like patches can potentially affect other chemical moieties on oxo-G surface, for example, endoperoxides( EPs). [16] Since the EP amount on oxo-G defines its toxicity, [16] it is important to understand the effect of aging on this parameter.T herefore, we appliedapreviously described fluorogenic probe F-AN-ON1, which releases fluorescent dye F in the presence of EPs (Scheme 1B,F igure 2E,F), [16] to probe aging-inducedc hanges of EP amountso no xo-G surface. In agreement with the expectations, we observed that freshlyp repared oxo-G 0 contained substantially more EPs than aged GOs as evidenced by the decreased rate of the F release (dF/dt) from 2.9 for oxo-G 0 to 1.6 for oxo-G 14d/4 8C and oxo-G 28d/ 4 8C (Figure 2E,F).…”

The Antibacterial Applications of Graphene and Its Derivatives

“…(1) Oxidative stress: ROS produced by GO suspension damage cellular components, such as lipids and proteins. After being internalized by cells, ROS cause mitochondrial dysfunction and DNA damage . By using a specially prepared GO coated atomic force microscopy (AFM) probe, researchers determined that the main interaction force between GO and the E. coli membrane is repulsive rather than adhesive.…”

Controlled Chemistry Approach to the Oxo‐Functionalization of Graphene

“…Ketones, carboxyl, or phenols located at the edges of defects can even become the major species . Also unpaired spins have been reported as part of the structure, as well as endo ‐peroxide groups that can be a source of toxicity towards cells . Also chinoide structures are plausible and stable motives.…”