Synthesis, Characterization and Models of Graphene Oxide

Biological Performance of Hexadeca-Substituted Metal Phthalocyanine/Reduced Graphene Oxide Nanobioagents

This study presents a tetra-substituted phthalonitrile derivative, namely, diethyl 2-(3,4-dicyano-2,5-bis(hexyloxy)-6-(4-(trifluoromethoxy)phenoxy)phenyl)malonate (a), cyclotetramerizing in the presence of some metal salts. The resultant hexadeca-substituted metal phthalocyanines [M= Co, Zn, InCl)] (b-d) were used for the modification of reduced graphene oxide for the first time. The effect of the phthalonitrile/metal phthalocyanines on biological features of reduced graphene oxide (rGO) was extensively examined by the investigation of antioxidant, antimicrobial, DNA cleavage, cell viability, and antibiofilm activities of nanobioagents (1-4). The results were compared with those of unmodified rGO (nanobioagent 5), as well. Modification of reduced graphene oxide with the synthesized compounds improved its antioxidant activity. The antioxidant activities of all the tested nanobioagents also enhanced as the concentration increased. The antibacterial activities of all the nanobioagents improved by applying the photodynamic therapeutic (PDT) method. All the phthalonitrile/phthalocyanine-based nanobioagents (especially phthalocyanine-based nanocomposites) exhibited DNA cleavage activities, and complete DNA fragmentation was observed for nanobioagents (1-4) at 200 mg/L. They can be used as potent antimicrobial and antimicrobial photodynamic therapy agents as well as Escherichia coli microbial cell inhibitors. As a result, the prepared nanocomposites can be considered promising candidates for biomedicine.

Graphene Oxide (GO) for the Treatment of Bone Cancer: A Systematic Review and Bibliometric Analysis

Cancer is a severe disease that, in 2022, caused more than 9.89 million deaths worldwide. One worrisome type of cancer is bone cancer, such as osteosarcoma and Ewing tumors, which occur more frequently in infants. This study shows an active interest in the use of graphene oxide and its derivatives in therapy against bone cancer. We present a systematic review analyzing the current state of the art related to the use of GO in treating osteosarcoma, through evaluating the existing literature. In this sense, studies focused on GO-based nanomaterials for potential applications against osteosarcoma were reviewed, which has revealed that there is an excellent trend toward the use of GO-based nanomaterials, based on their thermal and anti-cancer activities, for the treatment of osteosarcoma through various therapeutic approaches. However, more research is needed to develop highly efficient localized therapies. It is suggested, therefore, that photodynamic therapy, photothermal therapy, and the use of nanocarriers should be considered as non-invasive, more specific, and efficient alternatives in the treatment of osteosarcoma. These options present promising approaches to enhance the effectiveness of therapy while also seeking to reduce side effects and minimize the damage to surrounding healthy tissues. The bibliometric analysis of photothermal and photochemical treatments of graphene oxide and reduced graphene oxide from January 2004 to December 2022 extracted 948 documents with its search strategy, mainly related to research papers, review papers, and conference papers, demonstrating a high-impact field supported by the need for more selective and efficient bone cancer therapies. The central countries leading the research are the United States, Iran, Italy, Germany, China, South Korea, and Australia, with strong collaborations worldwide. At the same time, the most-cited papers were published in journals with impact factors of more than 6.0 (2021), with more than 290 citations. Additionally, the journals that published the most on the topic are high impact factor journals, according to the analysis performed, demonstrating the high impact of the research field.

Fabrication of r-GO/GO/α-Fe2O3/Fe2TiO5 Nanocomposite Using Natural Ilmenite and Graphite for Efficient Photocatalysis in Visible Light

Hematite (α-Fe₂O₃) and pseudobrookite (Fe₂TiO₅) suffer from poor charge transport and a high recombination effect under visible light irradiation. This study investigates the design and production of a 2D graphene-like r-GO/GO coupled α-Fe₂O₃/Fe₂TiO₅ heterojunction composite with better charge separation. It uses a simple sonochemical and hydrothermal approach followed by L-ascorbic acid chemical reduction pathway. The advantageous band offset of the α-Fe₂O₃/Fe₂TiO₅ (TF) nanocomposite between α-Fe₂O₃ and Fe₂TiO₅ forms a Type-II heterojunction at the Fe₂O₃/Fe₂TiO₅ interface, which efficiently promotes electron-hole separation. Importantly, very corrosive acid leachate resulting from the hydrochloric acid leaching of ilmenite sand, was successfully exploited to fabricate α-Fe₂O₃/Fe₂TiO₅ heterojunction. In this paper, a straightforward synthesis strategy was employed to create 2D graphene-like reduced graphene oxide (r-GO) from Ceylon graphite. The two-step process comprises oxidation of graphite to graphene oxide (GO) using the improved Hummer's method, followed by controlled reduction of GO to r-GO using L-ascorbic acid. Before the reduction of GO to the r-GO, the surface of TF heterojunction was coupled with GO and was allowed for the controlled L-ascorbic acid reduction to yield r-GO/GO/α-Fe₂O₃/Fe₂TiO₅ nanocomposite. Under visible light illumination, the photocatalytic performance of the 30% GO/TF loaded composite material greatly improved (1240 Wcm^-2). Field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) examined the morphological characteristics of fabricated composites. X-ray photoelectron spectroscopy (XPS), Raman, X-ray diffraction (XRD), X-ray fluorescence (XRF), and diffuse reflectance spectroscopy (DRS) served to analyze the structural features of the produced composites.

Enhancement of absorption capacity, optical and non-linear optical properties of graphene oxide nanosheet

We studied the absorption capacity, optoelectronic and non-linear optical (NLO) properties of graphene oxide nanosheet (GON) and its doped derivatives with aluminum (-Al) atoms. The investigations have been performed using three functionals (B3LYP, B3LYP-D3 and ωB97XD) of the density functional theory (DFT) associated to the basis set 6-31+G(d,p). Aluminum atoms were incorporated into GON at different sites in order to search for suitable candidates that could lead to the enhancement of NLO properties and decrease the band gap value of pristine graphene oxide. As per our molecular investigations, several doped molecular design schemes based on push-pull models of GON were proposed. The best electronic and NLO configurations responses highlight the doped derivatives which were obtained by replacement of carbon atoms which support the functional groups present on the honeycomb lattice of GON with -Al atoms.

Synthesis and Toxicity of Graphene Oxide Nanoparticles: A Literature Review of In Vitro and In Vivo Studies

Nanomaterials have been widely used in many fields in the last decades, including electronics, biomedicine, cosmetics, food processing, buildings, and aeronautics. The application of these nanomaterials in the medical field could improve diagnosis, treatment, and prevention techniques. Graphene oxide (GO), an oxidized derivative of graphene, is currently used in biotechnology and medicine for cancer treatment, drug delivery, and cellular imaging. Also, GO is characterized by various physicochemical properties, including nanoscale size, high surface area, and electrical charge. However, the toxic effect of GO on living cells and organs is a limiting factor that limits its use in the medical field. Recently, numerous studies have evaluated the biocompatibility and toxicity of GO in vivo and in vitro. In general, the severity of this nanomaterial's toxic effects varies according to the administration route, the dose to be administered, the method of GO synthesis, and its physicochemical properties. This review brings together studies on the method of synthesis and structure of GO, characterization techniques, and physicochemical properties. Also, we rely on the toxicity of GO in cellular models and biological systems. Moreover, we mention the general mechanism of its toxicity.

Preparation of magnetized iron oxide grafted on graphene oxide for hyperthermia application

Magnetic hyperthermia therapy (MHT) is a highly promising therapeutic modality for the treatment of different kinds of cancers and malignant tumors. The therapy is based on the concept that; iron oxide nanoparticles deposited at cancer sites can generate heat when exposed to an alternating current magnetic field or near infrared radiation and consequently destroying only the cancer cells by exploiting their vulnerability to heat. The fact that the treatment is at molecular level and that iron oxide nanoparticles provide more guided focus heating justifies its efficacy over treatment such as surgery, radiation therapy and chemotherapy. Nevertheless, the spread of MHT as the next-generation therapeutics has been shadowed by insufficient heating especially at the in vivo stage. This can be averted by modifying the iron oxide nanoparticle structure. To this end, various attempts have been made by developing a magnetic hybrid nanostructure capable of generating efficient heat. However, the synthesis method for each component (of the magnetic hybrid nanostructure) and the grafting process is now an issue. This has a direct effect on the performance of the magnetic hybrid nanostructure in MHT and other applications. The main objective of this review is to detail out the different materials, methods and characterization techniques that have been used so far in developing magnetic hybrid nanostructure. In view of this, we conducted a comprehensive review and present a road map for developing a magnetic hybrid nanostructure that is capable of generating optimum heat during MHT. We further summarize the various characterization techniques and necessary parameters to study in validating the efficiency of the magnetic hybrid nanostructure. Hopefully, this contribution will serve as a guide to researchers that are willing to evaluate the properties of their magnetic hybrid nanostructure.

Folic acid-conjugated raloxifene hydrochloride carbon nanotube for targeting breast cancer cells

Breast cancer is one of the leading causes of mortality specifically for the women. The existing therapy is not sufficient due to the lack of target specificity and drug resistance. Carbon nanotubes (CNTs) are one of the promising formulation approaches that show a promising effect to target specifically the cancer cells, with better cellular internalization. CNTs were prepared based on the modified Staudenmaier process, where temperature and stirring speed were found to be the most influencing factor for particle size and entrapment of the drug raloxifene hydrochloride (RLX). The optimized formulation was produced with drug loading of about 74.2 ± 4.67% and the average particle size of 234.2 ± 1.7 nm. The surface of the CNTs was functionalized by folic acid (FA), which helps to deliver the drug on the site of the cancer cells only in a target-specific manner. in vitro drug-release studies indicated that the drug release was dependent on the pH of the system. Cytotoxicity study clearly indicated the efficacy of the FA physically conjugated CNTs with affectivity induces apoptosis in the cancer cell line with the IC50 value of 43.57305 μg/ml. The fluorescence imagining study showed higher cellular internalization of the RLX compared with the pure drug and the RLX-CNT formulation.

Distinguishing characteristics and usability of graphene oxide based on different sources of graphite feedstock

Graphene oxide (GO) has gained popularity in scientific research and industry due to its superior properties, which can be controlled by the synthesis method and graphite feedstock. Despite the availability of different graphite sources, most of the reported studies used natural graphite flake (NGF) as a source of oxidation for GO synthesis. The effect of various alternative graphite feedstocks on the GO properties has not been investigated systematically. This study investigated the influence of graphite feedstock (natural and synthetic) on the characteristics and properties of GO via modified Hummer's method. Natural graphite flake (NGF), natural graphite powder (NGP), and synthetic graphite powder (SGP) were used as graphite feedstock in the study. Energy-dispersive X-ray analysis revealed that the GO produced using NGP (NGP-GO) has higher oxygen to carbon ratio in comparison to GO made from NGF (NGF-GO) and GO made from SGP (SGP-GO) (35.4, 32.7, and 32.2%, respectively), indicating higher oxidation degree for NGP-GO. Zeta potential analysis for NGP-GO, NGF-GO and SGP-GO were -47.8, -42.6 and -39.4 mV, respectively. Morphological analysis revealed that the structures of GO varied according to graphite feedstock, in which (NGP-GO) and (NGF-GO) were highly exfoliated (single-layered structure) while (SGP-GO) showed a multi-layered structure. Further testing was conducted by decorating silver (Ag) nanoparticles on the GO. The results showed that Ag could be uniformly decorated (no agglomeration) on the surface of GO-NGP, due to the presence of more functional groups. Subsequently, the antimicrobial property of Ag-NGP was the highest with an inhibition diameter of 14.7 ± 1.2 mm (30% higher than the other samples). In conclusion, the properties of GO can be tuned by selecting the suitable graphite feedstock and this might pave the way to new developments in the GO-based applications.