Graphene and graphene-based nanomaterials have great potential for various biomedical applications due to their unique physicochemical properties. However, how graphene-based nanomaterials interact with biological systems has not been thoroughly studied. This study shows that 24, 48, and 72 hr exposure of 2.4 μg/cm 2 of graphene oxide (GOX) and GOX modified with DAB-AM-16 and PAMAM dendrimers (GOXD and GOXP, respectively) did not exhibit toxicity to MCF-7 cells. However, higher graphene concentrations, such as 24 and 48 μg/cm 2 , induced low cytotoxic effects. The GOX, GOXD, and GOXP particles have a strong affinity with the cellular membrane. Cells that internalized the nanomaterials presented morphological alterations and modifications in the organization of microfilaments and microtubules compared with control cells. Then, cells were treated with 24 μg/cm 2 of GOX, GOXD or GOXP for 24 hr and recovered for an additional period of 24 hr in normal medium. Nanoparticles remained in the cytoplasm of some cells, apparently with no effect on cellular morphology, being consistent with the data found in the cell proliferation experiment, which showed that the cells remained alive up to 72 hr. K E Y W O R D Scell morphology, cell proliferation, Dendrimer, Graphene oxide, nano-bio interaction

Graphene oxide (GO) was chemically modified with a poly(propylene)imine Generation 3.0 dendrimer (DAB-Am-16). The characterization, structure and properties of hybrid graphene oxide/DAB-Am-16 dendrimer was studied by Raman spectroscopy, Fourier-Transforming Infrared Spectroscopy (FT-IR), X-Ray Photoelectron Spectroscopic (XPS), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis. After functionalized the hybrid material (GOD) can interact with copper and subsequently with hexacyanoferrate (III) ions (GODHCu). The GODHCu incorporated into a graphite paste electrode (20% w/w) was applied to an electrocatalytic detection of neurotransmitter L-dopamine using differential pulse voltammetry. The analytical curve showed a linear response in the concentration range from 1.0 Â 10 À7 to 1.0 Â 10 À5 mol L À1 with a corresponding equation Y(A) ¼ 1.706 Â 10 À5 þ 0.862 [Ldopamine] and a correlation coefficient r 2 ¼ 0.998. The detection limit was 6.36 Â 10 À7 mol L À1 with a relative standard deviation of ±4% (n ¼ 3) and an amperometric sensitivity of 0.862 A/mol L À1 .

The polyamidoamine dendrimer PAMAM was covalently bound to graphene oxide via amide formation between any peripheral amine group dendrimer and the carboxyl groups present in graphene oxide. This material (GOP) was characterized by different spectroscopic techniques, namely Raman Spectroscopy, X‐Ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FT‐IR) and X‐Ray Diffraction (XRD). The hybrid material was shown to adsorb silver, that in turn complexes with hexacyanoferrate (III) ions (GOPAgH). The complexed hybrid material was electrochemically investigated using cyclic voltammetry. Some electroanalytical parameters, such as different supporting electrolytes, the supporting electrolyte concentrations, hydrogen ion concentration effects and scan rate were evaluated in order to obtain optimum responses. The GOPAgH material was successfully tested in the electrocatalytic detection of Isoniazid using a graphite paste electrode with Limits of Detection and Quantification of 5.0×10−6 mol L−1 and 1.7×10−5 mol L−1, respectively.

This work describes the preparation and characterization of size-controlled zinc hexacyanoferrate (III) nanoparticles (ZnH). They were prepared using different proportions of water/formamide in the complexation reaction of Zn 2+ with [Fe III (CN) 6 ] 3À. The materials were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Ultraviolet-Visible Spectroscopy (UV-vis), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Cyclic Voltammetry (CV). The cyclic voltammograms of the modified graphite paste electrode with ZnH-1, ZnH-2, ZnH-3 and ZnH-4 showed a well-defined redox couple with formal potential (E u 0) = 0.94 AE 0.01 V (n=20 mV s À1 ; KCl 1.0 M)) attributed to the redox process [Fe II (CN) 6 ]/[Fe III (CN) 6 ] in the presence of Zn 2+. The dependence of particle size on the detection of sulfite was verified.

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This work describes the organofunctionalization and a complementary characterization and application of an octakis(3-chloropropyl)octasilsesquioxane (1) with 4-Amino-5-Phenyl-4H-[1,2,4]-Triazole-3-Thiol (2). The functionalized silsesquioxane (3) was characterized by nuclear magnetic resonance, X-ray diffraction, transmission electron microscopy and thermogravimetric analysis. After functionalized, the silsesquioxane can interact with copper chloride and subsequently with potassium hexacyanoferrate (III) (4). The hybrid composite formed (4) was characterized by FT-IR and diffuse reflectance. The compound 4 included into a work graphite paste electrode (20% w/w) was examined for chronoamperometric determination of L-Dopamine. The modified graphite paste electrode with compound 4 showed a linear response from 2.5×10 −5 at 4.0×10 −4 mol L −1 . The modified graphite paste electrode with 4 showed a detection limit of 2.08× 10 −4 mol L −1 with a relative standard deviation of ±2% (n = 3) and amperometric sensitivity of 0.136 A mol L −1 .

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A number of different metallic nanoparticles have been extensively investigated in recent years based on their diverse potential in biomedical and cancer applications, antibacterial activity, and chemical properties. Here, silver nitroprusside nanoparticles (AgNPs) were prepared from silver nitrate and sodium nitroprusside, and their anticancer activity was evaluated. AgNPs were prepared and characterized by Fourier transform infrared (FTIR), X-ray diffraction (DRX), scanning electron microscopy (SEM), X-ray dispersive energy spectroscopy (EDX), and transmission electron microscopy (TEM). In vitro tests were performed using two breast cancer cell lines, including a non-malignant breast epithelial cell line (MCF-10A) and a breast cancer cell line (MCF-7). The results obtained through cytotoxicity assays (MTT and resazurin) and bright-field microscopy revealed that AgNPs (3.0 mg/mL) exhibited specific selectivity for non-malignant breast epithelial cells. They were toxic to tumorigenic cells (MCF-7) with a lower selective toxicity to non-malignant breast epithelial cells (MCF-10A). In vivo imaging system (IVIS) imaging demonstrated the antitumor activity of AgNPs (3.0 mg/mL) compared to that of the control, and this was confirmed through histological analysis without any potential systemic toxicity. These results suggest that AgNPs possess potential anticancer applications in breast cancer treatment.