Water-Soluble Graphite Nanoplatelets Formed by Oleum Exfoliation of Graphite

Mukherjee, Arnab; Kang, JungHo; Kuznetsov, O. V.; Sun, Yong; Thaner, Ryan V.; Bratt, Ariana S.; Lomeda, Jay R.; Kelly, Kevin F.; Billups, W. E.

doi:10.1021/cm100808f

Cited by 37 publications

(29 citation statements)

References 35 publications

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“…Raman spectra of the initial graphite material and an SGS sample are depicted in Additional file 1: Figure S2. According to previous Raman studies [4], graphene can be identified by monitoring the position of the 2D band, whereby sulfonation of the phenyl groups and subsequent formation of the SGS sodium salt lead to repulsive interactions between the SO 3 − groups (to produce exfoliation), as evidenced by a slight shift in the 2D peak in Additional file 1: Figure S2. Functionalization by sulfonation has also been confirmed by XPS and TGA, which is provided in Additional file 1: Figures S3 and S4, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Samples were obtained from Mukherjee et al [4]. In their technique, highly exfoliated SGSs can be synthesized by sulfonation of commercially available graphite (particle size < 20 μm) in oleum to overcome the cohesive van deer Waals attractions between adjacent sheets.…”

Section: Methodsmentioning

confidence: 99%

“…We have recently demonstrated a facile route towards the synthesis of nanosized water-soluble sulfonated graphene sheets (SGSs) that use graphite as the starting material [4]. This method relies on the addition of phenyl radicals with subsequent sulfonation of the phenyl groups and produces fewer defects and holes that can be introduced into the graphene plates through the use of heavy sonication.…”

Section: Introductionmentioning

confidence: 99%

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Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells

et al. 2013

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Highly exfoliated sulfonated graphene sheets (SGSs), an alternative to graphene oxide and graphene derivatives, were synthesized, characterized, and applied to liver cancer cells in vitro. Cytotoxicity profiles were obtained using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, WST-1[2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, and lactate dehydrogenase release colorimetric assays. These particles were found to be non-toxic across the concentration range of 0.1 to 10 μg/ml. Internalization of SGSs was also studied by means of optical and electron microscopy. Although not conclusive, high-resolution transmission and scanning electron microscopy revealed variant internalization behaviors where some of the SGS became folded and compartmentalized into tight bundles within cellular organelles. The ability for liver cancer cells to internalize, fold, and compartmentalize graphene structures is a phenomenon not previously documented for graphene cell biology and should be further investigated.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells

et al. 2013

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“…6 However, a major impediment that hinders their application in the preparation of the functional materials as well as in biological systems is their inherent insolubility in different organic-aqueous solvents. Covalent chemical functionalization of GNS potentially overcomes these issues by creating functional groups on the surface of the nanosheet, which not only increases its dispersibility in various organic solvents 7,8 but also creates a band gap for applications in photonics and microelectronics. 9 In the case of biological applications, the primary requirement for GNS sample preparation is its dispersibility in water, biocompatibility and nontoxicity.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of amine functionalized graphite nanosheets and their water-soluble derivative for drug loading and controlled release

Chakravarty

Bhowmik

et al. 2015

New J. Chem.

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A facile route to synthesize amine (-NH 2 ) functionalized graphite nanosheets (AFGNS) by 2-step controlled chemical modification of microcrystalline graphite is described. The method begins with nitration by mixed acid (HNO 3 : H 2 SO 4 in 1 : 1 v/v ratio), followed by reduction with Na 2 S to form AFGNS. The AFGNS was reacted with carboxylic acid-terminated polyethylene glycol (PEG) chains (MeO-mPEG-COOH, M W = 5000 Da) in the presence of a carbodiimide coupling agent to obtain a water-soluble PEGylated AFGNS (P-AFGNS) composite.Anticancer drug doxorubicin (DOX) was loaded on this composite with a loading capacity of 0.296 mg mg À1for an initial concentration of 0.232 mg mL À1 DOX and 0.136 mg mL À1 of P-AFGNS and the release of DOX from this water-soluble DOX loaded P-AFGNS composite at two different temperatures was found to be strongly pH dependent.

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“…However, visibly, important discrepancies emerge. Indeed, some research groups propose that aryl radicals increase conductivity [12,13] whereas others support the opposite behavior. [9][10][11][12][13][14] From a purely chemical standpoint, it has been proposed by some groups that aryl radicals can be attached only at edges [13] whereas others found that the basal plane of graphene is reactive.…”

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On the Addition of Aryl Radicals to Graphene: The Importance of Nonbonded Interactions

Denis

2013

ChemPhysChem

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Dispersion-corrected density functional theory is utilized to study the addition of aryl radicals to perfect and defective graphene. Although the perfect sheet shows a low reactivity against aryl diazonium salts, the agglomeration of these groups and the addition onto defect sites improves the feasibility of the reaction by increasing binding energies per aryl group up to 27 kcal mol(-1). It is found that if a single phenyl radical interacts with graphene, the covalent and noncovalent additions have similar binding energies, but in the particular case of the nitrophenyl group, the adsorption is stronger than the chemisorption. The single vacancy shows the largest reactivity, increasing the binding energy per aryl group by about 80 kcal mol(-1). The zigzag edge ranks second, enhancing the reactivity 5.4 times with respect to the perfect sheet. The less reactive defect site is the Stone-Wales type, but even in this case the addition of an isolated aryl radical is exergonic. The arylation process is favored if the groups are attached nearby and on different sublattices. This is particularly true for the ortho and para positions. However, the enhancement of the binding energies decreases quickly if the distance between the two aryl radicals is increased, thereby making the addition on the perfect sheet difficult. A bandgap of 1-2 eV can be opened on functionalization of the graphene sheets with aryl radicals, but for certain configurations the sheet can maintain its semimetallic character even if there is one aryl radical per eight carbon atoms. At the highest level of functionalization achieved, that is, one aryl group per five carbon atoms, the bandgap is 1.9 eV. Regarding the effect of using aryl groups with different substituents, it is found that they all induce the same bandgap and thus the presence of NO(2), H, or Br is not relevant for the alteration of the electronic properties. Finally, it is observed that the presence of tetrafluoroborate can induce metallic character in graphene.

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Water-Soluble Graphite Nanoplatelets Formed by Oleum Exfoliation of Graphite

Cited by 37 publications

References 35 publications

Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells

Cytotoxicity and variant cellular internalization behavior of water-soluble sulfonated nanographene sheets in liver cancer cells

Synthesis of amine functionalized graphite nanosheets and their water-soluble derivative for drug loading and controlled release

On the Addition of Aryl Radicals to Graphene: The Importance of Nonbonded Interactions

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