Graphene oxide and its derivatives as promising In-vitro bio-imaging platforms

Intrinsic fluorescence and versatile optical properties of Graphene Oxide (GO) in visible and near-infrared range introduce this nanomaterial as a promising candidate for numerous clinical applications for early-diagnose of diseases. Despite recent progresses in the impact of major features of GO on the photoluminescence properties of GO, their modifications have not yet systematically understood. Here, to study the modification effects on the fluorescence behavior, poly ethylene glycol (PEG) polymer, metal nanoparticles (Au and Fe3O4) and folic acid (FA) molecules were used to functionalize the GO surface. The fluorescence performances in different environments (water, DMEM cell media and phosphate buffer with two different pH values) were assessed through fluorescence spectroscopy and fluorescent microscopy, while Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) and Scanning electron microscopy (SEM) were utilized to evaluate the modifications of chemical structures. The modification of GO with desired molecules improved the photoluminescence property. The synthesized platforms of GO-PEG, GO-PEG-Au, GO-PEG-Fe3O4 and GO-PEG-FA illustrated emissions in three main fluorescence regions (blue, green and red), suitable for tracing and bio-imaging purposes. Considering MTT results, these platforms potentially positioned themselves as non-invasive optical sensors for the diagnosis alternatives of traditional imaging agents. A correction for this article can be viewed at https://doi.org/10.1038/s41598-020-75090-

An improved method for fabrication of Ag-GO nanocomposite with controlled anti-cancer and anti-bacterial behavior; a comparative study

In this study, two green procedures for Silver-Graphene Oxide (Ag-GO) nanocomposite synthesis were investigated. As a common method, AgNO3 was first loaded on the GO surface and then was reduced and stabilized by walnut green husk extract, producing Ag-GO-I. As an innovative approach, GO was first exposed to the extract and then the AgNO3 was added as the second step, producing Ag-GO-Pi. Physicochemical properties, antibacterial and cytotoxicity activity of both nanocomposites were subsequently studied comparing with free silver nanoparticles (AgNPs) and pure GO. Based on the results, exposure of GO to the extract, as a reducing agent, at the first/last step of the synthesis process resulted in the fundamental differences in the final products. So that, high amounts of agglomerated silver nanoparticles were formed between the GO sheets, when using the common method, whereas in Ag-GO-Pi, small AgNPs were formed on the GO sheets without aggregation, entirely covering the sheets. Antibacterial and cytotoxic behavior of these nanomaterials could be compared as AgNPs > AgGO-Pi > Ag-GO-I. It is assumed that these differences are due to control of unwanted nucleation in the synthesis process that Ag nanoparticles are smaller with less agglomeration when the GO surfaces are pre-treated with reducing agent

Science map of Cochrane systematic reviews receiving the most altmetric attention score: a network analysis

The present study aimed to analyze and visualize the science map of Cochrane systematic reviews (CSRs) with high Altmetric attention score (AAS). On 2020-07-29, the altmetric data of the Cochrane Database of Systematic Reviews were obtained from the Altmetric database (Altmetric LLP, London, UK). Bibliometric data of the top 5% AAS of CSRs were extracted from the Web of Science. Keyword co-occurrence, co-authorship and co-citation network analyses were then employed using VOSviewer software. The random forest model was used to rank the importance of the altmetric resource. A total of 11222 CSRs with AAS were found (Total mentions: 305265), with Twitter being the most popular Altmetric resource. Consequently, the top 5% AAS (649 articles, mean AAS: 204.95, 95% confidence level: 18.95, mean citations: 123.68, 95% confidence level: 13.9) were included. Density mapping revealed female, adult and child as the most popular author keywords. According to network visualization, Helen V. Worthington (University of Manchester, Manchester, UK), the University of Oxford and UK had the greatest impact on the network at the author, organization and country levels respectively. AAS were weekly correlated with citations (rs=0.21) although citations were moderately correlated with policy document and blog mentions (rs=0.46 and rs=0.43). Cochrane systematic reviews received high levels of online attention, particularly in the Twittersphere and mostly from the UK. However, CSRs were rarely publicized and discussed using recently developed academic tools, such as F1000 prime, Publons and PubPeer

Blocking endocytosis: a novel cancer treatment

© 2016 Dr. Elham BidramThis thesis studied the modified GO as a potential therapeutic-tracking conjugate. The imaging/tracing properties and toxicity effects of the proposed system was investigated. This system has shown encouraging results for cancer therapy in a selectively toxic way considering the observed cytotoxic and synergistic effects with the conventional chemotherapeutic drugs

Hierarchical multifunctional graphene oxide cancer nanotheranostics agent for synchronous switchable fluorescence imaging and chemical therapy

A nanotheranostics platform was synthesized based on PEGylated graphene oxide–gold nanoparticles and specified with aptamer toward the MUC-1-positive tumor cells. Subsequently, it was loaded with doxorubicin, used for non-invasive fluorescence imaging and therapy of breast and colon tumors. The success of the nano-coating at each synthesis step was characterized through FTIR, XRD, TGA, FE-SEM, EDAX, Zeta-potential, and fluorescence spectroscopy. Besides, the ability of the designed platform in targeted imaging, drug delivery, and in vitro therapy were evaluated using fluorescence microscopy and flow cytometry. The selected aptamer acts as a quencher, resulting in an “on/off” fluorescence biosensor. When the aptamer specifically binds to the MUC-1 receptor, its double strands separate, leading to the drug release and the recovery of the fluorescence of (“On” state) at the excitation wavelength of 300 nm. Based on cell toxicity results, this platform has more toxicity toward the MUC-1-positive tumor cells (HT-29 and MCF-7) compared to MUC-1-negative cells (Hep-G2), representing its selective performance. Thus, this nano-platform can be introduced as a multifunctional cancer nanotheranostics system for tracing particular biomarkers, non-invasive imaging, and targeted chemotherapy

Author Correction: Graphene oxide and its derivatives as promising In-vitro bio-imaging platforms (Scientific Reports, (2020), 10, 1, (18052), 10.1038/s41598-020-75090-w)

This Article contains an error in the horizontal axis labels of Figures 9, 10, 11 and 12 where “Wavenumber” should read “Wavelength”. The correct Figures 9, 10, 11 and 12 appear below as Figure 1, 2, 3 and 4

Penicillin and Oxacillin Loaded on PEGylated-Graphene Oxide to Enhance the Activity of the Antibiotics against Methicillin-Resistant Staphylococcus aureus

Infectious diseases are known as the second biggest cause of death worldwide, due to the development of antibiotic resistance. To overcome this problem, nanotechnology offers some promising approaches, such as drug delivery systems that can enhance drug efficiency. Herein, a Graphene Oxide-polyethylene glycol (GO-PEG) nano-platform was synthesized and penicillin and oxacillin, two antibiotics that are ineffective against Methicillin-resistant S. aureus (MRSA), were loaded on it to improve their effectiveness. The nanocomposites were characterized using FTIR, XRD, UV–Vis, FE-SEM/EDX, and Zeta potential analyses, followed by an evaluation of their antibacterial activity toward MRSA. Based on the results, drug loaded GO-PEG nanocomposites with loading efficiencies of 81% and 92% for penicillin and oxacillin, respectively, were successfully synthesized. They showed a controlled release within six days. The zeta potential of GO-PEG-oxacillin and penicillin was −13 mV and −11 mV, respectively. The composites showed much more activity against MRSA (80–85% inhibition) in comparison to GO-PEG (almost 0% inhibition) and pure antibiotics (40–45% inhibition). SEM images of MRSA treated with GO-PEG-antibiotics showed a deformation in the structure of bacterial cells, which led to the collapse of their intracellular components. These results demonstrate the effectiveness of utilizing the GO-based nanoplatforms in enhancing the antibacterial activity of the antibiotics

Organoid technology : current standing and future perspectives

Organoids are powerful systems to facilitate the study of individuals’ disorders and personalized treatments. Likewise, emerging this technology has improved the chance of translatability of drugs for pre-clinical therapies and mimicking the complexity of organs, while it proposes numerous approaches for human disease modeling, tissue engineering, drug development, diagnosis, and regenerative medicine. In this review, we outline the past/present organoid technology and summarize its faithful applications, then, we discuss the challenges and limitations encountered by 3D organoids. In the end, we offer the human organoids as basic mechanistic infrastructure for “human modelling” systems to prescribe personalized medicines

Fractionation of graphene oxide single nano-sheets in water-glycerol solutions using gradient centrifugation

A centrifugation method for the separation and fractionation of graphene oxide (GO) single nano-sheets in the size range of 150-850 nm is reported. The measured electrophoretic mobility of the fractionated single sheets ranges from -0.2 to -1.4 μm.cm/V·s where the interpreted zeta potentials vary from -3 mV to -17 mV with increasing sheet size. The single GO sheets show auto-fluorescence in the visible range of 350-650 nm using an excitation wavelength of 200 nm. Furthermore, the GO nano-sheets functionalized using PEG are found to be non-cytotoxic in in-vitro at concentrations up to 90 μg/ml, with a small reduction in cell viability -10%- at 260μg/ml. The observed concentration-dependence of the cytotoxicity potentially explains the differing conclusions on cytotoxic potential reported in the literature. The GO nano-sheets therefore have the potential to be used as fluorescent drug delivery carriers of specific size