Binding Characteristics of Anticancer Drug Doxorubicin with 2D

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C: Physical Processes in Nanomaterials and Nanostructures

Binding Characteristics of Anticancer Drug Doxorubicin with 2D Graphene and Graphene Oxide: Insights from Density Functional Theory Calculations and Fluorescence Spectroscopy Hakkim Vovusha, Debapriya Banerjee, Manoj Kumar Yadav, Francesco Perrozzi, Luca Ottaviano, Suparna Sanyal, and Biplab Sanyal J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.8b04496 • Publication Date (Web): 17 Aug 2018 Downloaded from http://pubs.acs.org on August 19, 2018

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The Journal of Physical Chemistry

Binding Characteristics of Anticancer Drug Doxorubicin with 2D Graphene and Graphene Oxide: Insights from Density Functional Theory Calculations and Fluorescence Spectroscopy

Hakkim Vovusha,1, 2 Debapriya Banerjee,2 Manoj Kumar Yadav,1 Francesco Perrozzi,3 Luca Ottaviano,3 Suparna Sanyal2 and Biplab Sanyal1*

* Correspondence to: [email protected] 1

Department of Physics and Astronomy, Uppsala University, Box-516,

Ångströmlaboratoriet, 751 20, Uppsala, Sweden 2

Department of Cell and Molecular Biology, Uppsala University, Box-596, BMC, 75124,

Uppsala, Sweden 3

Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio 10,

67100 Coppito-L'Aquila, Italy

1 ACS Paragon Plus Environment

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ABSTRACT: There is a perpetual interest in identifying suitable nanocarriers for drug delivery. In this regard, graphene based two dimensional (2D) materials have been proposed and demonstrated as the drug carriers. In this paper, we have investigated the adsorption characteristics of a widely used anticancer drug, Doxorubicin (DOX) on graphene (G) and graphene oxide (GO) by density functional theory calculations, fluorescence and x-ray photoelectron spectroscopies. From the calculated structural and electronic properties, we have concluded that G is a better binder of DOX compared to GO, which is also supported by our fluorescence measurements. The binding of DOX to G is mainly based on strong π-π stacking interactions. Consistent with this result, we also found that the sp2 regions of GO interact with DOX stronger than the sp3 regions attached with functional groups; the binding is characterized by - and hydrogen bonding interactions, respectively.


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INTRODUCTION In the last decades, two-dimensional (2D) nanomaterials have been demonstrated as useful tools for targeted drug delivery.1-6 Due to their small size and large surface-area to volume ratio, high stability, good biocompatibility, and easy surface modification properties they offer the advantages of tunable life-time, permeability enhancement and receptor targeting specificity.7,8 The use of nanoparticles is particularly advantageous for targeted drug delivery in cancerous cells due to their specific uptake “in vivo” in tumoral tissues, which is essentially governed by fluidodynamic properties inside the blood micro-vessels.9,10 This, indeed, can waive the drug designer from an elaborate bio-chemical-engineering of the nanoparticles for enhancing their specific uptake through the cancer cell-membranes. Targeted drug delivery using 2D nanomaterials has recently become a very hot topic in nanomedicine.11-15 The use of nonspherical nanoparticles with higher surface-area to volume ratio, such as nanoplatelets of 2D materials, can be particularly advantageous for their ability to be incorporated to cancerous tissues in vivo, that is demonstrated by their enhanced residence times in blood vessels.9 For targeting cancer cells, tuning the size, surface, and shape of the nanomaterials can be important, this depends on the nature of the tumor. It has been shown that smaller nanoparticles accumulate more easily in the blood stream than larger ones. In this context, various nanomaterials such as tantalum sulfide nanosheets, antimonene quantum dots, 2D MoS2 nanosheets and black phosphorous have been tried for cancer treatment.16-22 Due to the biocompatibility and biodegradability properties, the carbon-based 2D materials such as Graphene (G) or Graphene Oxide (GO) are the subjects of the most extensive and potentially promising investigations as drug carriers.23,24 G is a single atom thick layer of sp2 hybridized carbon atoms arranged in a hexagonal network.25-35 Hence it has a purely flat surface, which does not offer natural functionalization sites. Another feature of relevance of G related interaction with living matter is that its surface is strongly hydrophobic.36 GO, on the 3 ACS Paragon Plus Environment


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other hand, is a graphene (G) sheet decorated with epoxide and hydroxyl groups on the basal plane as the major components and carbonyl and carboxyl groups on the edges as the minor components. Thus, GO offers both sp2 and sp3 hybridized carbons.31-35 At variance with G, GO provides built-in functionalization sites, which can accordingly fine tune its chemical and physical properties and, most interestingly, offer an easily adjustable flake-size distribution and excellent water solubility.36 Because of the presence of different functional groups on the surface of GO, the drugs and/or other biomolecules can easily bind to the two dimensional scaffold of GO.15 This, in turn, strongly reduces the mobility of these molecules and facilitates their delivery to tumoral cells. Furthermore, it has been demonstrated that by tuning the GO flake-size, GO internalization into cells can be controlled.37,38 The hydrophobic to hydrophilic gradual transition from fully oxidized GO to graphene has been reported in the literature and the results shows that wetting properties of ideal 2D surfaces in practical bio-applications the very important parameter for internalization into the cells is the nano-graphene size rather than its reduction degree as demonstrated.39,40 Doxorubicin (DOX) is a well-known anti-cancer drug commonly used in the treatment of a wide range of cancer diseases. Once internalized in the cells, DOX intercalates in the DNA double helix and thereby prevents DNA replication and cell division process.3 Thus, targeted delivery of DOX to the cancerous cells is highly essential to avoid its adverse effects on other cells and tissues during cancer treatment. In this regard, use of 2D carbon materials with specificity for incorporation in the cancerous cells can provide a big advantage. GO has been tested as a carrier for DOX and the interaction between the two has been studied experimentally41. By preparing a GO-DOX nanohybrid, Yang et al. have studied the loading and release behavior of DOX on GO.42 They reported that DOX binding to GO involves mainly π-π interaction and may be stabilized by hydrogen bonding between the two. However, as GO possesses both sp3 (carbon bearing functional groups) and sp2 (without any functional group)


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carbon atoms, DOX can have different interactions with the GO surface, which calls for a detailed analysis at a molecular level. In this regard, a comparative study for DOX binding to G is also essential as it provides a purely sp2 hybridized carbon containing surface. The interaction of nanostructures and 2D materials with the living matter is a field of investigation, which is tremendously expanding and it’s reported in the literatures based on the current progress of cancer nanomedicines and novel 2D nanomaterials.16-19 Borras and coworkers have discussed specific toxicity issues of Graphene oxide nanoflakes with living matter.43 The outcome is that GO toxicity is very much size dependent. However, once cancer therapy is considered, conventional drugs and DOX are themselves inherently toxic agents. Accordingly, in cancer therapy the use of GO may not be the primary cause of toxicity. Here, first principles electronic structure calculations become useful to analyze the interactions in a quantum mechanical level. In this paper, we have studied the binding of DOX to G and GO using density functional theory (DFT) calculations, which provide in depth understanding for the structure and energetics of various interactions between DOX and G / GO. Our theoretical results have been confirmed by fluorescence spectroscopy along with the estimation of the binding constants in solution. Our studies clearly suggest G as a better binder and thus, a potentially improved carrier for DOX delivery into the cells.

MATERIALS AND METHODS Chemicals. DOX was purchased from Sigma Aldrich. G was from graphene supermarket

[.]). GO solution in water with a concentration of 0.5 mg/mL was prepared using a modified Hummers method as described by Perozzi et al.44 Characterization of the GO sample with 5 ACS Paragon Plus Environment


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(i) X-ray Photoelectron Spectroscopy - XPS spectra of GO have been acquired with a PHI 1257 spectrometer equipped with a monochromatic Al Kα source (hν =1486.6 eV) with pass energy of 11.75 eV corresponding to an overall experimental resolution of 0.25 eV, and have been fitted with Voigt line shapes and Shirley backgrounds. The GO solution was spin coated on 100 nm Au(100)/Si in order to perform XPS analysis. The C 1s spectra are fitted with the sum of four components assigned to C atoms belonging to: aromatic rings and hydrogenated carbon (C=C/C-C, C-H, 284.9 eV), hydroxyl groups and epoxy groups (C-O-C, 286.9 eV), carbonyl groups (C=O, 288.4 eV), and carboxyl groups (C=O(OH), 289.3 eV). The relative weight of each component is 49%, 41%, 8% and 2%, respectively, while the overall C/O ratio is ~2 (Supplementary Fig. S1) (ii) Scanning electron microscopy (SEM) - SEM images have been acquired with a Zeiss-Gemini LEO 1530 system by spin coating the diluted GO solution on 300 nm SiO2/Si. SEM images show that the size of GO sheets ranges between tens to hundreds of nm (Supplementary Fig. S2). Raman spectroscopy - Raman analysis on the same but non-sonicated GO is reported in (Perrozzi et al.).44 UV-Vis fluorescence measurements to monitor DOX binding to G and GO. The fluorescence spectra of DOX were recorded in Hitachi F-7000 fluorescence spectrophotometer using a quartz cuvette of path length 1 cm with excitation at 470 nm. In order to study the interaction of DOX with the G/GO, aqueous suspensions of G/GO in water were progressively added to 5 M solution of DOX. The resulting mixtures were shaken for 10 mins and their spectra were recorded. The quenching of DOX fluorescence at 560 nm in the presence of the different quenchers (G/GO) was plotted according to the Stern-Volmer equation F0 /F = 1 + KSV [Q],


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where F0 represents the fluorescence in the absence of quencher G/GO, F represents the fluorescence in the presence of quencher G/GO and KSV is the Stern-Volmer constant. Computational Methods. Ab initio density functional calculations have been carried out employing projector augmented wave (PAW) method and a plane wave basis as implemented in the VASP code.45 We have used Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation for the treatment of exchange correlation functional.46 In order to account for van der Waals interaction between DOX and the substrates, we have employed DFT-D2 approach.47 The pristine G surface was modeled employing a supercell approach. The 25.56 Å X 24.60 Å surface containing 240 carbon atoms, with 10 carbon rings along X-axis and 12 carbon rings along Y-axis was repeated along X-and Y-directions whereas a vacuum of 20 Å was maintained along Z-direction. For the sake of consistency, the same supercell size was retained for modelling graphene oxide. The Brillouin zone sampling was done with a 3x3x1 Monkhorst-Pack k-point mesh. Geometries were optimized by minimizing Hellmann Feynman forces to 0.01 eV/Å. The final energies were calculated with a 5x5x1 k-mesh. In the structural model of GO, the hydroxyl and epoxy functional groups have been placed according to the paper by Guo et al.48 To mimic the experimental structure of GO following our XPS data, we have introduced vacancies randomly on the GO surface and carbonyl, carboxyl functional groups and hydrogens have been introduced at those vacancy sites to saturate the dangling bonds (model referred as GO1). The binding energies of DOX with GO and G were calculated using the equation: BE=ESUB+DOX ‒ (ESUB+EDOX) where BE, ESUB+DOX, ESUB and EDOX are binding energy, total energy of the complex, substrate (GO or G) and DOX respectively.

RESULTS AND DISCUSSION



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Model systems. The chemical structures for the present investigation have been shown in Figure 1. In pristine graphene (G), C-C bond length in the ring is about 1.42 Å. The structural model of GO contains three C8O2(OH)2 islands distributed in the form of an equilateral triangle. Each of these units has two hydroxyl and two epoxy groups. In GO1, we have one C8O2(OH)2 unit and one vacancy near this unit. The dangling bonds at the vacancy site are saturated with hydrogen atom, carbonyl and carboxyl groups.

GO

GO1

DOX

Figure 1: Chemical structures of two model GO systems and DOX used in this study. The upper panel shows the top view and the lower panel shows the side view. DOX is a tetracyclic molecule with two planar, aromatic hydroxyanthraquinone rings, which form a chromophore and one non-planar, nonaromatic ring attached to an amoinoglycosidic side chain. DOX contains various functional groups such as ─C=O, ─COOROH, ─OH, ─OR and ─NH2. To model the complexes of DOX with GO/G, we have considered two orientations of the DOX molecule, one with all four rings facing (A1 part) the surface of the nanomaterial, and the other, with the amoniglycosidic chain (A2 part) facing the surface. These models with G are referred as G-DOX-A1 and G-DOX-A2 respectively and the GO complexes are named similarly.


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Structure and Energetics of Nanomaterial-DOX Complexes. As mentioned above, we have performed energy minimization of the two complexes G-DOX-A1 and G-DOX-A2. The total energy of G-DOX-A1 complex was lower than G-DOX-A2 by 1.27 eV, therefore we continued only with this complex for further analysis. Figure 2 shows the energy minimized structure of G-DOX-A1, where all three planar rings of DOX show π-π interaction with the π orbital of C of G with a typical distance of about 3.25 Å between the two. In addition, CH-π and OH-π interactions are also observed in the complex. Moreover, due to the interaction with G, the intramolecular hydrogen bond lengths of DOX were modified. The binding energy of the complex was estimated as 1.94 eV. Next, we have compared the total energies of the two GO-DOX complexes, with DOX placed on the top of the C8O2(OH)2 unit. As in G, the GO-DOX-A1 complex was 0.61 eV more stable than GO-DOX-A2, due to which, further calculations are done only with GO-DOX-A1. Since, GO has both sp3 and sp2 regions, another model was built with DOX placed in the sp2 region of GO; this complex was named GO-DOX-A3. The energy minimized structures of GODOX-A1 and GO-DOX-A3 are depicted in Figure 3. In GO-DOX-A1 complex, planar

Figure 2: Energy minimized structure of G-DOX-A1, (left) top view, (right) side view.



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rings of DOX form π-π interaction with the G ring of GO with a distance about 3.31 Å. The carbonyl and the hydroxyl groups of DOX form hydrogen bonds with the hydroxyl group of GO with the distance of 1.86 and 2.39 Å, respectively. The calculated binding energies are 1.74 and 2.10 eV for GO-DOX-A1 and GO-DOX-A3, respectively. Binding energy in the case of GO-DOX-A3 is higher than that of GO-DOX-A1 due to the presence of both hydrogen bonding and π-π interaction in the GO-DOX-A3 whereas GO-DOX-A1 has only hydrogen bonded interaction between DOX and GO.

Figure 3: Energy minimized structures of GO-DOX-A1 (top panel) and GO-DOX-A3 (bottom panel). In both panels, the left figure shows the top view and the right panel shows the right view.


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Interaction of DOX with GO1 has also been studied with two different orientations of DOX with respect to the surface of GO1. A1 part of the DOX facing towards C8O2(OH)2 island and pore region is named as GO1-DOX-A1 and the A2 part of DOX facing towards GO1 is named as GO1-DOX-A2. Similar to GO-DOX-A3 complex, we have placed DOX on the sp2 region of GO1, which is named as GO1-DOX-A3. Among these configurations, GO1-DOXA3 (depicted in Figure 4) is more stable than the others. The calculated binding energy for the GO1-DOX-A3 is 1.80 eV.

Figure 4: Energy minimized structure of GO1-DOX-A3, (left) top view (right) side view. It is clear from the above discussion that overall, the binding affinity of DOX with G is more favorable than GO. This may be due to different surface properties of G and GO. Similar results were also obtained by Radic et. al. where they studied binding of natural amphiphiles with G and GO.49 In Ref 49, binding of peptides, cellulose and fatty acids with graphene and graphene oxide were studied for the application of drug delivery and nanomaterial engineering. We have also reported binding properties of nucleobases and aromatic amino acids with G and GO flakes.15 Depending on the hydrocarbon content of the molecules, the adsorption strength varies and graphene has a higher binding with those molecules than graphene oxide due to different surface functionalization of graphene oxide.



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It has also been observed that the interaction between DOX and the substrates causes significant changes in the intramolecular hydrogen bonding of DOX. The calculated geometrical parameters for the intramolecular hydrogen bond of DOX and G/GO-DOX are presented in Table 1. Table 1: Intramolecular Hydrogen Bond Length of Free DOX Molecule and its Complex with G and GO Hydrogen bond length (Å) O1···H

O2···H

O3···H

DOX

1.85

1.73

2.00

G-DOX-A1

1.48

1.54

1.85

GO-DOX-A1

1.55

1.53

1.84

GO-DOX-A3

1.53

1.53

1.86

GO1-DOX-A3

1.47

1.55

1.85

The three hydrogen bonds in the free DOX molecule change in a non-trivial manner when it is adsorbed on various substrates. These changes are crucially dependent on the relative orientation of the molecule and hence, the corresponding interaction with the substrates. However, for all the substrates, the bond lengths decrease compared to those of the free molecule. Fluorescence Spectroscopy Measurements. In order to study the interaction of DOX with G and GO, the changes in fluorescence of DOX in presence of G and GO were studied as shown in Figure 5.


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Figure 5: Stern-Volmer plot of interaction of DOX with G and GO. The inset shows wavelength scan of DOX alone or with –G and –GO in an otherwise identical condition. Aqueous suspensions of G/GO were added in increasing amounts to DOX solution (5 M). The fluorescence of DOX at 560 nm was quenched upon addition of both G and GO. However, addition of G produced a greater quenching of DOX fluorescence than GO when added in equal amounts (inset Figure 5). The quenching of DOX fluorescence with different amounts of G and GO is plotted according to the Stern-Volmer equation (Figure 5). In a typical plot, the quenching of fluorescence is determined by the expression, F0/F against the concentration of the additive (G/GO), where F and F0 are the fluorescence in the presence and absence of G/GO, respectively. The quenching of fluorescence showed linear dependence on G/GO concentration. The data were fit will linear functions, which clearly suggest G as a stronger binder of DOX than GO. The DOX loading capacity of GO with various functionalizations has been reported.6 In an original study the loading capacity of DOX on GO has been estimated as 2.35 mg/mg.42 Our experimental result suggests three to four times higher loading capacity of G in comparison to GO. 13 ACS Paragon Plus Environment


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Electronic Structure Analysis. To understand the interaction of DOX with G and GO further, electronic structure of these complexes has been calculated by means of total density of states (TDOS) and projected density of states (PDOS).

Figure 6. Total densities of states of pristine G/GO, G/GO-DOX complexes and projected density of states for the DOX molecule adsorbed on the substrates.

Figure 6 shows calculated DOS for both the pristine G/GO, the G/GO-DOX and adsorbed DOX molecule. After adsorption of DOX molecule, DOS of G is increased further and two new peaks (one is at -1.8 eV and another one is at 0.5 eV) were observed near the Fermi level. Similarly, two new peaks are observed at -1.7 eV and 0.4 eV after the adsorption of DOX on GO. Charge densities corresponding to these energies are shown in Figure 7. It is clearly seen that most of the electronic charge density is localized on the adsorbed DOX molecule. In addition to the electronic structure, charge transfer has also been calculated using Bader charge analysis. It is found that charge transfer of about 0.06 electron takes place from DOX to G/GO.


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GO-DOX-A1

G-DOX-A1

Figure 7. Energy resolved electronic charge density of G-DOX-A1 and GO-DOX-A1 complex.es Charge density is shown for an eigenvalue at -1 eV for G-DOX-A1 and at an eigenvalue of -1.8 eV for GO-DOX-A1. Both the eigenvalues are measured w.r.t. the Fermi level. Finally, we calculated the difference in charge density plots for composites and isolated systems. This is mathematically represented as where

,

and

,

are charge densities of the graphene-DOX composite,

graphene and DOX molecule respectively. The results are shown in Figure 8. The yellow and cyan colors indicate accumulation and depletion of charge densities respectively. The charge accumulation and depletion occur at the regions of interaction between the two subsystems.



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Figure 8. Charge density difference plots are shown for several configurations of G and GO complexes with DOX. The yellow and cyan colors indicate accumulation and depletion of charge densities respectively. For the nomenclature of the complexes, the readers are referred to the text of the paper.

CONCLUSION In this study, adsorption of DOX molecule on monolayer G and GO has been studied by fluorescence spectroscopy and ab-initio density functional theory. From our calculations, we have observed that the binding of DOX molecule to G is more favored than GO, which is also confirmed by fluorescence spectroscopy. This is due to the dominant  interaction between DOX and G. On GO surfaces, DOX has a stronger interaction with the sp2 region than the sp3 region. G-DOX complex is stabilized by π···π and CH-π interaction whereas GO-DOX complex is stabilized by hydrogen bonding and π···π interactions. The modification of the intramolecular hydrogen bond lengths in DOX, charge transfer from the substrates to DOX and the changes in electronic densities of states are the direct consequences of adsorption. These 16 ACS Paragon Plus Environment

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adsorption characteristics may become helpful in suitably choosing carbon nanomaterials for targeted drug delivery.

Acknowledgements This work is supported by the grants from the Swedish Research Council (2016-05366), Swedish Research Links (2017-05447) to B.S, Swedish Research Council (2014-4423), Research Environment Grant (2016-06264) and Knut and Alice Wallenberg Foundation (KAW 2017.0055) grants to S.S. We gratefully acknowledge supercomputing time allocation by the Swedish National Infrastructure for Computing (SNIC) and PRACE-2IP project ‘CHARTERED2’ resource Salomon cluster based in Czech Republic at the IT4Innovations for performing the computations.

Supporting Information Available Supporting Information Available: XPS spectrum and SEM image of graphene oxide. This material is available free of charge via the Internet at http://pubs.acs.org.



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REFERENCES 1. Liu, Z.; Robinson, J. T.; Sun X. M.; Dai, H. J. PEGylated Nanographene Oxide for Delivery of Water-Insoluble Cancer Drugs. J. Am. Chem. Soc. 2008, 130, 10876–10877. 2. Zhang, L. M.; Xia, J. G.; Zhao, Q. H.; Liu, L. W.; Zhang, Z. J. Functional Graphene Oxide As A Nanocarrier For Controlled Loading and Targeted Delivery of Mixed Anticancer Drugs. Small 2010, 6, 537–544. 3. Zhou, T.; Zhou, X.; Xing, D. Controlled Release of Doxorubicin from Graphene Oxide Based Charge-Reversal Nanocarrier. Biomaterials 2014, 35, 4185-4194. 4. Webster, D. M.; Sundaram, P.; Byrne. M. E. Injectable Nanomaterials for Drug Delivery: Carriers, Targeting Moieties, And Therapeutics. Eur. J. Pharm. Biopharm. 2013, 84, 1–20. 5. Farokhzad, O. C.; Langer, R. Impact of Nanotechnology on Drug Delivery. ACS Nano 2009, 3, 16-20. 6. Zhuqing, Wang.; Lucio, C. C.; Gang, W. Recent Advances in the Synthesis of Graphene-Based Nanomaterials for Controlled Drug Delivery, Applied Sciences 2017, 7, 1175. 7. Nicolardi, S.; Yuri, E. M.; Burgt, V. D.; Jeroen, D. C.; Wuhrer, M.; Hokke, C. H.; Chiodo. F. Structural Characterization of Biofunctionalized Gold Nanoparticles by Ultrahigh-Resolution Mass Spectrometry. ACS Nano 2017, 11, 8257-8264. 8. Howorka, S. Building Membrane Nanopores. Nature Nanotechnol. 2017, 12, 619–630. 9. Decuzzi, P. Facilitating the Clinical Integration of Nanomedicines: The Roles of Theoretical and Computational Scientists. ACS Nano 2016, 10, 8133–8138. 10. Chan, W. C. W.; Khademhosseini, A.; Parak, W.; Weiss, P. S. Cancer: Nanoscience and Nanotechnology Approaches. ACS Nano 2017, 11, 4375-4376.


Page 19 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


11. Ulbrich, K.; Holá, K.; Šubr, V.; Bakandritsos, A.; Tuček, J.; Zbořil, R. Targeted Drug Delivery with Polymers and Magnetic Nanoparticles: Covalent and Noncovalent Approaches, Release Control, and Clinical Studies. Chem. Rev. 2016, 116, 5338-5431. 12. Orza, A.; Casciano, D.; Biris, A. Nanomaterials for Targeted Drug Delivery to Cancer Stem Cells. Drug Metab. Rev. 2014, 46,191-206. 13. Huang, J.; Zong, C.; Shen, H.; Cao, Y.; Ren, B.; Zhang, Z. Tracking The Intracellular Drug Release from Graphene Oxide Using Surface-Enhanced Raman Spectroscopy. Nanoscale 2013, 5, 10591–10598. 14. Chimene, D.; Alge, D. L.; Gaharwar, A. K. Two-Dimensional Nanomaterials for Biomedical Applications: Emerging Trends and Future Prospects. Adv. Mater. 2015, 27, 7261–7284. 15. Vovusha, H.; Sanyal, S.; Sanyal, B. Interaction of Nucleobases and Aromatic Amino Acids with Graphene Oxide and Graphene Flakes. J. Phys. Chem. Lett. 2013, 4, 37103718. 16. Shi, J.; Kantoff, P. W.; Wooster, R.; Farokhzad, O. C. Cancer Nanomedicine: Progress, Challenges and Opportunities. Nat. Rev. Cancer 2016, 17, 20-37. 17. Liu, Y.; Ji, X.; Liu, J.; Tong, W. W. L.; Askhatova, D.; Shi, J. Tantalum Sulfide Nanosheets as a Theranostic Nanoplatform for Computed Tomography Imaging‐ Guided Combinatorial Chemo‐Photothermal Therapy. Adv. Funct. Mater. 2017, 27, 1703261. 18. Tao, W.; Ji, X.; Xu, X.; Islam, M. A.; Li, Z.; Chen, S.; Saw, P. E.; Zhang, H.; Bharwani, H.; Guo, Z.; et al. Antimonene Quantum Dots: Synthesis and Application as Near‐ Infrared Photothermal Agents for Effective Cancer Therapy. Angew. Chem. Int. Ed. 2017, 56, 11896 –11900.



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19. Zhu, X.; Ji, X.; Kong, N.; Chen, Y.; Mahmoudi, M.; Xu, X.; Ding, L.; Tao, W.; Cai, T.; Li, Y.; et al. Intracellular Mechanistic Understanding of 2D MoS2 Nanosheets for Anti-ExocytosisEnhanced Synergistic Cancer Therapy. ACS Nano 2018, 12, 2922−2938. 20. Qiu, M.; Wang, D.; Liang, W.; Liu, L.; Zhang, Y.; Chen, X.; Sang, D. K.; Xing, C.; Li, Z.; Dong, B.; et al. Novel Concept of the Smart NIR-light–controlled Drug Release of Black Phosphorus Nanostructure for Cancer Therapy. Proc. Natl. Acad. Sci. U. S. A. 2018, 115, 501-506. 21. Tao, W.; Zhu, X.; Yu, X.; Zeng, X.; Xiao, Q.; Zhang, X.; Ji, X.; Wang, X.; Shi, J.; Zhang, H.; Mei, L. Black Phosphorus Nanosheets as a Robust Delivery Platform for Cancer Theranostics. Adv. Mater. 2017, 29, 1603276. 22. Shao, J.; Xie, H.; Huang, H.; Li, Z.; Sun, Z.; Xu, Y.; Xiao, Q.; Yu, X-F.; Zhao, Y.; Zhang, H.; et al. Biodegradable Black Phosphorus-Based Nanospheres for in vivo Photothermal Cancer Therapy. Nat.Commun. 2016, 7, 12967. 23. Weaver, C. L.; LaRosa, J. M.; Luo, X.; Cui, X. T. Electrically Controlled Drug Delivery from Graphene Oxide Nanocomposite Films. ACS Nano, 2014, 8, 1834–1843. 24. Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. Electric Field Effect in Atomically Thin Carbon Films. Science 2004, 306, 666– 669. 25. Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Katsnelson, M. I.; Grigorieva, I. V.; Dubonos, S. V.; Firsov, A. A. Two-dimensional Gas of Massless Dirac Fermions in Graphene. Nature 2005, 438, 197–200. 26. Kravets, V. G.; Grigorenko, A. N.; Nair, R. R.; Blake, P.; Anissimova, S.; Novoselov, K. S.; Geim, A. K. Spectroscopic Ellipsometry Of Graphene And An Exciton-Shifted Van Hove Peak In Absorption. Phys. Rev. B 2010, 81,155413. 20 ACS Paragon Plus Environment

Page 21 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


27. Rana, F.; George, P. A.; Strait, J. H.; Dawlaty, J.; Shivaraman, S.; Chandrashekhar, M.; Spencer, M. G. Carrier Recombination And Generation Rates For Intravalley And Intervalley Phonon Scattering In Graphene. Phys. Rev. B 2009, 79,115447. 28. Park, S.; Ruoff, R. S. Chemical Methods for the Production of Graphenes. Nat. Nanotechnol. 2009, 4, 217–224. 29. Elias, D. C.; Nair, R. R.; Mohiuddin, T. M. G.; Morozov, S. V.; Blake, P.; Halsall, M. P.; Ferrari, A. C.; Boukhvalov, D. W.; Katsnelson, M. I.; Geim, A. K.; et al. Control of Graphene's Properties by Reversible Hydrogenation: Evidence for Graphane. Science 2009, 323, 610–613. 30. Bonaccorso, F.; Sun, Z.; Hasan, T.; Ferrari, A. C. Graphene Photonics and Optoelectronics. Nat. Photonics 2010, 4, 611–622. 31. Park, S.; An, J.; Jung, I.; Piner, R. D.; An, S. J.; Li, X.; Velamakanni, A.; Ruoff, R. S. Colloidal Suspensions of Highly Reduced Graphene Oxide in a Wide Variety of Organic Solvents. Nano Lett. 2009, 9, 1593–1597. 32. Karlický, F.; Datta, K. K. R.; Otyepka, M.; Zboril, R. Halogenated Graphenes: Rapidly Growing Family of Graphene Derivatives. ACS Nano 2013, 7, 6434–6464. 33. Li, Y.; Yuan, H.; Bussche, A.; Creighton, M.; Hurt, R. H.; Kane, A. B.; Gao, H. Graphene Microsheets Enter Cells through Spontaneous Membrane Penetration At Edge Asperities and Corner Sites. Proc. Natl. Acad. Sci. U. S. A. 2013, 110, 12295– 12300. 34. Dreyer, D. R.; Park, S.; Bielawski, C. W.; Ruoff, R. S. The Chemistry of Graphene Oxide. Chem. Soc. Rev. 2010, 39, 228– 240. 35. Rafiee, J.; Mi, X.; Gullapalli, H.; Thomas, A. V.; Yavari, F.; Shi, Y.; Ajayan, P. M.; Koratkar, N. A. Wetting Transparency Of Graphene. Nat. Mater. 2012, 11, 217–222.



Page 22 of 24

36. Tang, H.; Sun, L.; He, H. Water Soluble Reduced Graphene Oxide As An Efficient Photoluminescence Quencher For Semiconductor Quantum Dots. Opt. Mater. 2017, 64, 9-12. 37. Zhang, G.; Ma, J.; Wang, J.; Li, Y.; Zhang, G.; Zhang, F.; Fan, X. Lipase Immobilized on Graphene Oxide As Reusable Biocatalyst. Ind. Eng. Chem. Res. 2014, 53, 19878– 19883. 38. Sun, X.; Liu, Z.; Welsher, K.; Robinson, J. T,; Goodwin, A.; Zaric, S.; Dai, H. NanoGraphene Oxide for Cellular Imaging and Drug Delivery. Nano. Res. 2008, 3, 203–212. 39. Francesco, P.; Salvatore, C.; Emanuele, T.; Vincenzo, P.; Sandro, S.; Giulia, F.; Luca, O. Reduction Dependent Wetting Properties Of Graphene Oxide. Carbon 2014, 77, 473 – 480. 40. Russier, J.; Treossi, E.; Scarsi, A. ; Perrozzi, F.; Dumortier, H.; Ottaviano, L.; Meneghetti, M.; Palermo, V.; Bianco. A. Size-Dependent Impact Of Graphene Oxide On Phagocytic Cells: Evidencing The "Mask Effect". Nanoscale 2013, 5, 11234. 41. Wu, S.; Zhao, X.; Li, Y.; Du, Q.; Sun, J.; Wang, Y.; Wang, X.; Xia, Y.; Wang, Z.; Xia, L. Adsorption Properties of Doxorubicin Hydrochloride Onto Graphene Oxide: Equilibrium, Kinetic and Thermodynamic Studies. Materials 2013, 6, 2016-2042. 42. Yang, X.; Zhang, X.; Liu, Z.; Ma, Y.; Huang, Y.; Chen, Y. High-Efficiency Loading and Controlled Release of Doxorubicin Hydrochloride on Graphene Oxide. J. Phys. Chem. C 2008, 112, 17554–17558. 43. De Marzi, L.; Ottaviano, L.; Perrozzi, F.; Nardone, M.; Santucci, S.; Lapuente, J.; Borras, M. E. Flake Size-Dependent Cyto And Genotoxic Evaluation Of Graphene Oxide On In Vitro A549, Caco2 And Vero Cell Lines. J. Biol. Regul. Homeost. Agents. 2014, 28, 281-289.


Page 23 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


44. Francesco, P.; Stefano, P.; Maurizio, D.; Federico, B.; Patrizia, D. M.; Sandro, S.; Michele, N. Emanuele, T.; Vincenzo, P.; Luca, O. Use of Optical Contrast To Estimate the Degree of Reduction of Graphene Oxide. J. Phys. Chem. C 2013, 117, 620–625 45. Kresse, G.; Furthmuller, J. Efficient Iterative Schemes for Ab Initio Total-Energy Calculations Using a Plane-Wave Basis Set. Phys. Rev. B. 1996, 54, 11169-11186. 46. Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865. 47. Grimme, S. Semiempirical GGA-Type Density Functional Constructed With A LongRange Dispersion Correction. J. Comp. Chem. 2006, 27, 1787. 48. Guo, Y.; Lu, X.; Weng, J.; Leng, Y. Density Functional Theory Study of the Interaction of Arginine-Glycine-Aspartic Acid with Graphene, Defective Graphene, and Graphene Oxide. J. Phys. Chem. C 2013, 117, 5708-5717. 49. Radic, S.; Geitner, N. K.; Podila, R.; Ka¨kinen, A.; Chen, P.; Ke, P. C.; Ding, F. Competitive Binding of Natural Amphiphiles with Graphene Derivatives. Sci. Rep. 2013, 3, 2273.



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Binding Characteristics of Anticancer Drug Doxorubicin with 2D

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