Polymer-functionalized Graphene Oxide Research Articles

Synergistic effect of polymer functionalized graphene oxide system for breast cancer treatment

The multifaceted drug carrier system is an emerging trend in delivering chemotherapeutic drugs and photosensitizers for the synergistic effect. In this work, we have designed a functionalized graphene oxide (GO) based carrier system for combined chemo-photodynamic therapeutic effects. Doxorubicin (DOX) and rose bengal (RB) were entrapped on the surface of GO via hydrophobic and π-π stacking interactions. The functional group determination, crystalline properties, surface morphology, and hydrodynamic size were evaluated using FT-IR, XRD, SEM, TEM, AFM, and DLS analysis. At 24 h, the entrapment efficiency was 65 % DOX and 40.92 % RB, and the loading capacities were 16.9 % DOX and 5.68 % RB observed at 30 min. The drug release percentage was higher in pH-2.6 rather than in pH-5.5, 6.8, and 7.4 pH environments. The in-vitro toxicity analysis using the LDH assay reveals that the DOX and RB co-loaded carriers had a significant cytotoxic effect on MCF-7 cells, indicating that the carrier could improve the therapeutic efficacy of DOX. Morphological changes were studied using inverted light microscopy; the cells were irradiated with a laser 525 nm 10 J/cm2 for 2 min 51 sec, and it was observed that the DOX and RB co-loaded carrier with laser-irradiated cells exposed the high-level morphological changes with the occurrence of apoptotic cell death. Compared to free DOX, the DOX/RB co-loaded carrier + laser had an efficient anticancer activity, as confirmed by DAPI staining cell uptake, flow cytometry, and intracellular ROS generation analysis. The DOX and RB co-loaded carrier clearly exhibits the RB-mediated photodynamic action on MCF-7 cells in response to external laser light irradiation. It permits an on-demand dual-payload release to trigger an instantaneous photodynamic and chemo treatment for cancer cell eradication. Finally, the ensuing dual-agent release is probable to successfully fight cancer via a synergistic effect.

Amino‐terminated hyperbranched polymer functionalized graphene oxide with in situ trapped silver nanoparticles for high‐performance antibacterial nonwoven fabric

AbstractAntibacterial fabric with high thermal stability and mechanical strength is important for personalized protection, especially under the background of coronavirus pandemic (COVID‐19). This paper presents a facile approach toward high‐efficient antibacterial polypropylene spunbonded nonwoven fabrics (SNFs), which are decorated by a composite of graphene oxide embedded with silver nanoparticles (AgNPs/GO) through dip‐coating and in situ reduction effect of pre‐introduced amino‐terminated hyperbranched polymer (HBP‐NH2). Typically, HBP‐NH2 was grafted onto the GO nanosheets, then silver ions were trapped and self‐reduced by the HBP‐NH2 to generate silver nanoparticles decorated GO. The produced AgNPs are uniformly dispersed on the GO with a size of 13 nm. As an antibacterial coating, the Ag/GO composite could tightly wrap the SNFs fibers through the dip‐padding method, capable of enhancing the thermal stability and mechanical property of SNFs. The treated SNFs exhibited excellent antibacterial activities (~99.9%) against both Echerisia coli and Staphylococcus aureus, promising important potential for biomedical and personal protection applications.

Efficient removal of phenolic contaminants from wastewater samples using functionalized graphene oxide with thermo-sensitive polymer: Adsorption isotherms, kinetics, and thermodynamics studies

In this study, a facile strategy was reported for the first time to prepare 2-vinylpyridine/thermosensitive polymer functionalized graphene oxide to be applied as the nanoadsorbent for efficient removal of phenol and 2, 4-dichlorophenol compounds in the wastewater samples by ultra-performance liquid chromatography. Fourier-transform infrared spectroscopy, thermogravimetric analysis, carbon, hydrogen, and nitrogen elemental analysis, scanning electron microscope, and N2 adsorption-desorption isotherms characterized the functional groups and structures. Experimental factors including pH, contact time, temperature, amount of adsorbent dosage, and the initial concentration of phenol and 2, 4-dichlorophenol compounds were studied to optimize the removal procedure. The optimal conditions for phenol removal were recorded at pH=7, contact time of 10 min, the adsorbent dosage of 0.005 g, and temperature of 298 K. For 2, 4-dichlorophenol, the experimental conditions for the removal process were pH=8, the adsorbent dosage of 0.005 g, and contact time of 5 min at 298 K. The experimental results correlated well with the pseudo-second-order kinetics and suggested that the removal of phenol and 2, 4-dichlorophenol from an aqueous solution follows Langmuir isotherm model. The maximum Langmuir sorption capacity obtained was 333.33 and 103.092 mg g−1 at 298 K for phenol and 2, 4- dichlorophenol, respectively. Thermodynamic analysis indicated that the process was feasible and spontaneous (phenol: ΔG = -8.199 to -8.733 kJ mol−1 and 2, 4- dichlorophenol: ΔG = -14.796 to -15.069 kJ mol−1) and exothermic in nature (phenol: ΔH = -1821.51 J mol−1 and 2, 4- dichlorophenol: ΔH= -18325.7 J mol−1). The maximum removal efficiency of phenol and 2, 4-dichlorophenol compounds were 99% and 89%, respectively. Thus, the prepared nanoadsorbent can be used as an ideal adsorbent for the recycling removal of phenolic contaminants from wastewater samples.

Efficient Gene Silencing in Intact Plant Cells Using siRNA Delivered By Functional Graphene Oxide Nanoparticles

AbstractDelivery of small interfering RNA (siRNA) to intact plants for gene silencing mainly relies on viral vectors and Agrobacterium‐mediated transformation due to the barrier of intact plant cell wall. Here, we reported that polymer functionalized graphene oxide nanoparticles (GONs) enable siRNA transfer into intact plant cells and bring about efficient gene silencing. We found that sheeted GONs could efficiently load siRNA to form small sized, near‐spheroidal GONs‐siRNA complex, which could be across the cell wall and internalize in the plant cell. The GONs‐siRNA exhibited transient and strong silencing (97.2 % efficiency) in plant tissues at 24 h after treatment and returned to normal level at 5 days after treatment. This method has the obvious advantages of efficient, transient, simple, stability and well biocompatibility, which should greatly stimulate the application of nanomaterials as gene‐engineering tools in plant research.

Efficient Gene Silencing in Intact Plant Cells Using siRNA Delivered By Functional Graphene Oxide Nanoparticles.

Delivery of small interfering RNA (siRNA) to intact plants for gene silencing mainly relies on viral vectors and Agrobacterium-mediated transformation due to the barrier of intact plant cell wall. Here, we reported that polymer functionalized graphene oxide nanoparticles (GONs) enable siRNA transfer into intact plant cells and bring about efficient gene silencing. We found that sheeted GONs could efficiently load siRNA to form small sized, near-spheroidal GONs-siRNA complex, which could be across the cell wall and internalize in the plant cell. The GONs-siRNA exhibited transient and strong silencing (97.2 % efficiency) in plant tissues at 24 h after treatment and returned to normal level at 5 days after treatment. This method has the obvious advantages of efficient, transient, simple, stability and well biocompatibility, which should greatly stimulate the application of nanomaterials as gene-engineering tools in plant research.

Preparation of matrix-grafted graphene/poly(poly(ethylene glycol) methyl ether methacrylate) nanocomposite gel polymer electrolytes by reversible addition-fragmentation chain transfer polymerization for lithium ion batteries

A structural design and appropriate morphology of polymer-functionalized graphene oxide are occupied to optimize nanocomposite polymer electrolytes. The nanocomposite gel polymer electrolytes (GPEs) based on poly(poly (ethylene glycol) methyl ether methacrylate and RAFT agent-functionalized graphene oxide [P(PEGMA/GO-S-(thiobenzoyl)thioglycolic acid (STTA))] have been successfully prepared by in-situ polymerization method in different ratio of GO-STTA and crosslinking by poly(ethylene glycol) diallyl (PEGDA). The P(PEGMA/GO-STTA) GPE with 0.5 wt% of GO-STTA exhibited a high ionic conductivity of 5.5 mS cm−1 at room temperature, a superior lithium transfer number (t+) value of 0.61, and electrochemical window up 4.7 V. The GPE based P(PEGMA/GO-STTA0.5%) indicated 92% coulombic efficiency, the charge capacity value of 191.7 mAh g−1, and capacity retention was about 92% after 100 cycles at 0.1C. P(PEGMA/GO-STTA) GPEs showed great potential for lithium ion battery with high safety and long cycle life.

Polyvinyl Alcohol Polymer Functionalized Graphene Oxide Decorated with Gadolinium Oxide for Sequestration of Radionuclides from Aqueous Medium: Characterization, Mechanism, and Environmental Feasibility Studies.

Uranium (U(VI)) and thorium (Th(IV)) ions produced by the nuclear and mining industries cause water pollution, thereby harming the environment and human health. In this study, gadolinium oxide-decorated polyvinyl alcohol-graphene oxide composite (PGO–Gd) was developed using a simple hydrothermal process to treat U(VI) and Th(IV) ions in water. The developed material was structurally characterized by highly advanced spectroscopy and microscopy techniques. The effects of pH, equilibration time and temperature on both radionuclides (U(VI) and Th(IV)) adsorption by PGO–Gd were examined. The PGO–Gd composite adsorbed both metal ions satisfactorily, with adsorption capacities of 427.50 and 455.0 mg g−1 at pH 4.0, respectively. The adsorption properties of both metal ions were found to be compatible with the Langmuir and pseudo–second-order kinetic models. Additionally, based on the thermodynamic characteristics, the adsorption was endothermic and spontaneous. Furthermore, the environmental viability of PGO–Gd and its application was demonstrated by studying its reusability in treating spiked surface water. PGO–Gd shows promise as an adsorbent in effectively removing both radionuclides from aqueous solutions.

Electrochemical Detection of 4-Nitrophenol by Using Graphene Based Nanocomposite Modified Glassy Carbon Electrodes: A Mini Review

This article describes the fabrication of electrochemical devices for the detection of a key environmental pollutant, 4-Nitrophenol (4-NPh). 4-NPh is a requirement for the synthesis of organophosphate pesticides. These pesticides are mostly used in the agricultural sector to obtain a high yield of agricultural products. The use of 4-NPh in the agricultural field results in poisonous levels of this compound in the soil and water. Different techniques have been used for its transformation by biological and chemical degradation. However, these strategies not only created highly toxic pollutant but also need fast operation and time consuming processes. In this background, we have reported a broad and efficient review of the electrochemical reduction of 4-NPh as a feasible alternate method. In this review paper, graphene oxide (GO), reduced graphene oxide (rGO), N-doped graphene oxide, functionalized graphene oxide, metallic nanoparticles coated graphene oxide, metal oxides covered on rGO, polymer functionalized graphene oxide and hybrids materials functionalized with graphene oxide (hydroxyl apatite and β-cyclodextrin) which have been fabricated on a glassy carbon electrode (GCE) to enhance the electrocatalytic reduction and increase the sensor activity of 4-NPh are discussed. We have also described the effects of a few interfering phenolic pollutants such as aminophenol, hydroquinone, o-nitrophenol (o-NPh), trinitrotoluene, trinitrophenol, 2, 4-dinitrophenol (4-DNPh) and nitrobenzene. In the paper, easy and more effective electrochemical methods for the detection of 4-NPh with graphene- based nanocomposites modified on GCE for 4-NPh detection are summarized and discussed.

High effective enrichment of U(VI) from aqueous solutions on versatile crystalline carbohydrate polymer-functionalized graphene oxide.

The removal of uranium on various sorbents has been widely employed in recent times. However, the limited sorption capacities of these sorbents inhibit the actual application of the radionuclide in actual environments. The development of a novel material with high sorption capacity and superior regeneration for the removal of uranium is highly desirable. Therefore, a versatile class of crystalline carbohydrate polymers (COF) was prepared from organic compounds. Moreover, COF-functionalized graphene oxide (COF/GO) was synthesized and tested for the removal of U(VI) from aqueous solutions. The batch characterization showed that COF was vertically oriented on the surface of GO using diboronic acid as nucleation sites. The maximum removal capacity of U(VI) on COF/GO reached 117.67 mg g-1, and was attributed to a huge void ratio and various oxygen-bearing functional groups. In addition, the inner-sphere surface-complexation dominated the U(VI) removal, and the adsorption mechanism of inner-sphere surface-complexation was transferred into surface precipitation with increasing reaction time. COF/GO can be converted into conductive carbon and reduced GO (C/rGO) nanocomposite, which has high specific capacitance. These results suggested that GO-based materials can be considered as promising candidates for the enrichment of U(VI) and energy storage.

A novel electrochemiluminescent immunoassay for diclofenac using conductive polymer functionalized graphene oxide as labels and gold nanorods as signal enhancers

Diclofenac (DCF) is among the pharmaceutical compounds of concern based on its nocuousness in environment. In this work, a novel electrochemiluminescent (ECL) immunosensor for detecting DCF was constructed using poly(etherimide)-poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) functionalized graphene oxide and CdSe@CdS quantum dots (QDs-PEI-GO/PEDOT) as bioreceptor for conjugating DCF antibody to magnify signal. It is worth noting that this is the first time GO/PEDOT has been applied to ECL sensor field. Compared with GO, GO/PEDOT exhibited a higher conductivity and more stable chemical property, indicating that the proposed immunosensor would possess stronger and more stable luminescence performance. In addition, the electrode was modified with gold nanorods (AuNRs) which increase the load capacity of DCF coating antigen through Au-N bond. Competitive immunoassay method was chosen for structuring immunosensor where polyclonal antibody (pAb) against DCF exhibited high-affinity recognition of DCF, which greatly improved the sensitively and selectivity of sensor. Consequently, the proposed immunosensor gratified in DCF detection with low detection limit (LODs) of 0.33 pg mL−1 (S/N = 3), and displayed high stability and sensitivity, which initiated a new route for DCF determining.

Synthesis of polymer-functionalized nanoscale graphene oxide with different surface charge and its cellular uptake, biosafety and immune responses in Raw264.7 macrophages

Polymer-functionalized graphene oxide (GO) has superior properties such as large surface area, extraordinary mechanical strength, high carrier mobility, good stability in physiological media and low cytotoxicity, making it an attractive material for drug and gene delivery. Herein, we successfully synthesized GO with an average size of 168.3 nm by a modified Hummers' method. Branched polyethylenimine (PEI) and 6-armed polyethylene glycol (PEG) functionalized GO complexes (GO-PEI and GO-PEG) with different zeta potentials of 47.2 mV and −43.0 mV, respectively, were successfully synthesized through amide linkages between the COOH groups of GO and the NH2 groups of PEI and PEG. Then, the interactions between GO-PEI and GO-PEG complexes and Raw264.7 mouse monocyte-macrophage cells were investigated. The GO-PEI and GO-PEG complexes could both be internalized by Raw264.7 cells. However, compared with the GO-PEG complex, the GO-PEI complex showed higher intracellular delivery efficiency in Raw264.7 cells. Moreover, it was found that the GO-PEI complex not only gathered in endosomes but also in the cytoplasm, whereas GO-PEG gathered in endosomes only. The MTT tests showed that both GO-PEI and GO-PEG complexes exhibited very low cytotoxicity towards Raw264.7 cells when at a low concentration. The cellular immune response test demonstrated the GO-PEG complex enhanced the secretion of IL-6, illustrating it was more stimulus towards macrophage cells. The above results indicated that the GO-PEI complex, with a positive surface charge, demonstrated better potential to be used in effective drug and gene delivery.

Natural polymer functionalized graphene oxide for co-delivery of anticancer drugs: In-vitro and in-vivo

The present study focuses on the development of a chitosan functionalized nanobiocomposite for the co-delivery of two anti-cancer drugs camptothecin (CPT) and 3,3′‑Diindolylmethane (DIM). The difference in the mechanism of action of the two drugs makes them a promising candidate to produce a synergistic effect against breast cancer. Herein a nanobiocomposite was developed by functionalizing a natural polymer chitosan to graphene oxide nanoparticles and decorated with folic acid. The nanobiocomposite thus synthesized was loaded with camptothecin and 3,3′‑Diindolylmethane and characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible spectroscopy (UV) and atomic force microscopy (AFM).Biocompatibility was assayed by hemolysis and anti-inflammatory assay. The cellular toxicity was measured by 3‑(4,5‑Dimethylthiazol‑2‑yl)‑2,5‑Diphenyltetrazolium Bromide (MTT), Sulforhodamine B (SRB) and cell death assay against MCF-7 cell lines. Further in vivo studies were carried out to analyze the biodistribution of the drug, blood biochemical analysis and bioavailability of the drug. The data revealed a significant increase in anticancer activity after co-loading of CPT and DIM to the nanocarrier. Also in-vivo studies revealed that DIM successfully masked the toxic effects produced by CPT.

Polymer-confined growth of perforated MoSe2 single-crystals on N-doped graphene toward enhanced hydrogen evolution.

The edge and corner atoms of 2D transition metal dichalcogenides (TMDCs) are the main electrocatalytically active sites for electrochemical reaction. Here, we demonstrate an approach to generate abundant edge/corner atoms in molybdenum diselenide (MoSe2) nanocrystals supported by nitrogen-doped graphene (NG) which consequently leads to significantly enhanced hydrogen evolution reaction (HER) activity. These structures were fabricated by firstly absorbing the Mo-containing precursor within polymer-functionalized graphene oxide, then selenized to obtain MoSe2 nanocrystals on the surface, and finally H2 etching was performed to form perforated structures. The use of a functional polymer as an absorption matrix efficiently mitigates aggregation which allows us to obtain MoSe2 single-crystals of ∼150 nm in lateral dimension, while maintaining high MoSe2 loading. We observed a remarkably enhanced electrocatalytic activity resulting from a significantly increased abundance of edge/corner atoms in hydrogen evolution measurements. Specifically, with this perforated MoSe2/NG-modified cathode, current densities of -1 and -10 mA cm-2 were realized with the overpotentials of only 30 and 106 mV, along with a small Tafel slope of 57 mV dec-1 and large exchange current density of 127.4 μA cm-2 in 0.5 M H2SO4. Such an efficient strategy also opens doors for the unparalleled design and fabrication of TMDC-based nanocomposites for electrochemical applications.

Self-assembly of metal–organic frameworks and graphene oxide as precursors for lithium-ion battery applications

We fabricated composites of Fe2O3/reduced graphene oxide as lithium-ion batteries anode material with controlled structures by employing self-assembly of metal–organic frameworks (MOFs) and polymer-functionalized graphene oxide as precursors. By electrostatic interaction, the negatively charged MOFs, Prussian Blue (PB), are assembled on poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene oxide (positive charge). Then the PB cubes become FeOOH nanosheets when treated with sodium hydroxide. Upon further annealing, the FeOOH nanosheets transform to Fe2O3 nanoparticles while the graphene oxide become reduced graphene oxide simultaneously. It was found that the composites have good performance as anode of lithium-ion battery. This work shows a new way for self-assembling MOFs and 2D materials.

Preferential Delivery of Anticancer Drug to Nucleic Acids Using Polymer Functionalized Graphene Oxide as Nanocarrier

Preferential Delivery of Anticancer Drug to Nucleic Acids Using Polymer Functionalized Graphene Oxide as Nanocarrier

Atomic thin titania nanosheet-coupled reduced graphene oxide 2D heterostructures for enhanced photocatalytic activity and fast lithium storage

Realizing practical high performance materials and devices using the properties of 2D materials is of key research interest in the materials science field. In particular, building well-defined heterostructures using more than two different 2D components in a rational way is highly desirable. In this paper, a 2D heterostructure consisting of atomic thin titania nanosheets densely grown on reduced graphene oxide surface is successfully prepared through incorporating polymer functionalized graphene oxide into the novel TiO2 nanosheets synthesis scheme. As a result of the synergistic combination of a highly accessible surface area and abundant interface, which can modulate the physicochemical properties, the resultant heterostructure can be used in high efficiency visible light photocatalysis as well as fast energy storage with a long lifecycle.

Novel sulfonated polyimide/zwitterionic polymer-functionalized graphene oxide hybrid membranes for vanadium redox flow battery

Hybrid membranes (SPI/ZGO) composed of sulfonated polyimide (SPI) and zwitterionic polymer-functionalized graphene oxide (ZGO) are fabricated via a solution-casting method for vanadium redox flow battery (VRB). Successful preparation of ZGO fillers and SPI/ZGO hybrid membranes are demonstrated by FT-IR, XPS and SEM, indicating that ZGO fillers is homogeneously dispersed into SPI matrix. Through controlling the interfacial interaction between SPI matrix and ZGO fillers, the physicochemical properties, e.g., vanadium ion barrier and proton transport pathway, of hybrid membranes are tuned via the zwitterionic acid-base interaction in the hybrid membrane, showing a high ion selectivity and good stability with the incorporated ZGO fillers. SPI/ZGO-4 hybrid membrane proves a higher cell efficiencies (CE: 92–98%, EE: 65–79%) than commercial Nafion 117 membrane (CE: 89–94%, EE: 59–70%) for VRB application at 30–80 mA cm−2. The assembled VRB with SPI/ZGO-4 membrane presents a stable cycling charge–discharge performance over 280 times, which demonstrates its excellent chemical stability under the strong acidic and oxidizing conditions. SPI/ZGO hybrid membranes show a brilliant perspective for VRB application.

Polymer Functionalized Graphene Oxide: A Versatile Nanoplatform for Drug/Gene Delivery

Polymer Functionalized Graphene Oxide: A Versatile Nanoplatform for Drug/Gene Delivery

Upper-critical solution temperature (UCST) polymer functionalized graphene oxide as thermally responsive ion permeable membrane for energy storage devices

A UCST polymer functionalized graphene oxide as a thermally responsive ion permeable membrane.

Soluble conducting polymer-functionalized graphene oxide for air-operable actuator fabrication

A soluble conducting polymer composite with graphene oxide showed air-operable actuation behavior under different voltages.