Chitosan Graphene Oxide Nanocomposites Research Articles

Encapsulated iodine–chitosan graphene oxide nanocomposite: fabrication and evaluation for antibacterial activity

ABSTRACT Chronic wounds pose a significant challenge to wound care professionals and have substantial cause of socioeconomic implications worldwide. This study focuses on the development of a gel containing encapsulated iodine–chitosan graphene oxide nanopockets (I-CH-GO-NPOs) with a comprehensive evaluation to discern its potential in enhancing the wound healing trajectory for full thickness chronic wounds. The prepared I-CH-GO-NPOs gel showed higher antibacterial property of 0.00513 ± 0.00014 mg/ml against gram-positive Staphylococcus aureus bacteria. Further, in vivo wound healing efficacy of I-CH-GO-NPOs was evaluated in Sprague-Dawley rats which showed a significant increase of 99.89 ± 2.2% in the wound contraction.

Interphase percolation phenomena in chitosan-graphene oxide nanocomposites, the role of water content

Interphase percolation phenomena in chitosan-graphene oxide nanocomposites, the role of water content

Negative electrical tunability of chitosan–graphene oxide nanocomposites

Herein, we report negative anomalous electrical tunability of the nanocomposite chitosan and graphene oxide (CS–GO) films based upon the dependence of dielectric constant and resistivity on DC bias. The origin of such anomalous tunability can be traceable to the reversible transformation of GO to reduced graphene oxide. In this transformation, H+ ions are released from water or GO side groups and those of $${\text{NH}}_{3}^{ + }$$ from CS; both ions participate in the reversible reduction process. Here, the capacitance exhibits negative tunability such that the dielectric constant increases and the resistivity decreases with increasing of DC bias. To probe this new phenomenon, we studied GO concentrations from 0 to 15 wt.% and water contents from 0 to 25 wt.%. Our results suggest that chitosan–GO nanocomposites can be readily prepared for the development of novel devices required in flexible organic electronics.

Chitosan-graphene oxide nanocomposites as water-solubilising agents for rotenone pesticide

In the present work, the feasibility of chitosan-graphene oxide (CS-GO) nanocomposites, namely CS-GO 1% (w/w), CS-GO 2% (w/w) and CS-GO 3% (w/w) as water-solubilising agents for rotenone pesticide was evaluated for the first time. The CS-GO nanocomposites were characterised by using FTIR, SEM, TEM and XRD analyses. The interaction of nanocomposites with rotenone was investigated through adsorption study involving several experimental parameters such as solution pH, initial concentration and contact time. Additionally, the desorption study was carried out using HCl and NaOH as desorption agents. Based on correlation coefficient (R2), the adsorption kinetic data were best described by the pseudo-first order equation while the adsorption equilibrium data were correlated well with the Langmuir isotherm model. The GO nanoparticle aggregates have a spherical shape with size ranged from 1.40 to 34.7 nm. The crystallinity of CS was increased following interaction with GO, whereby the intensity of diffractive peak at 2θ = 20.42° was increased to more than 4000 counts. Based on Langmuir isotherm model, CS-GO 3% (w/w) exhibited the highest adsorption capacity for rotenone with Q value of 92.59 mg/g. The main mechanism for interaction of CS-GO nanocomposites with rotenone was through formation of hydrogen bond. The presence of -OH, -COOH and -NH functional groups on CS-GO nanocomposites significantly contributed to water-solubilising mechanism. The CS-GO 1% (w/w), CS-GO 2% (w/w) and CS-GO 3% (w/w) nanocomposites were able to increase the solubility of rotenone in water by 34.40%, 38.80% and 46.30%, respectively.

Synthesis and application of chitosan/tripolyphosphate/graphene oxide hydrogel as a new drug delivery system for Sumatriptan Succinate

This study investigated the performance of chitosan-graphene oxide nanocomposite for the controlled release of the Sumatriptan Succinate (SS) drug. Various analytical methods (i.e., SEM, TEM, AFM, TGA, XRD, and FT-IR) were used to characterize the crystalline structure, molecular structure, and morphology of the fabricated nanocomposites. The effective parameters, including pH, adsorbent amount, temperature, and contact time, on the adsorption of SS on nanocomposite, were optimized. The adsorption mechanism was determined as Langmuir isotherm (R2 = 0.9976), representing the monolayer adsorption with the highest adsorption capacity of 45.4 mg/g. The addition of GO resulted in a noticeable increase (100%–200%) in the swelling degree and a decrease in drug release rates (20%- 45%) of the fabricated nanocomposites compared with the chitosan hydrogel. As the percentage of GO in hydrogel beads increases, drug release occurs less rapidly and in a controlled manner. Eventually, antibacterial activity and cytotoxicity of the prepared nanocomposite beads were evaluated, which confirmed their antibacterial properties and biocompatibility.

Design and Characterization of Chitosan-Graphene Oxide Nanocomposites for the Delivery of Proanthocyanidins.

IntroductionIn the last years, the utilization of phytomedicines has increased given their good therapeutic activity and fewer side effects compared to allopathic medicines. However, concerns associated with the biocompatibility and toxicity of natural compounds, limit the phytochemical therapeutic action, opening the opportunity to develop new systems that will be able to effectively deliver these substances. This study has developed a nanocomposite of chitosan (CS) functionalized with graphene oxide (GO) for the delivery of proanthocyanidins (PAs), obtained from a grape seed extract (Ext.).MethodsThe GO-CS nanocomposite was covalently bonded and was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM) and by dynamic light scattering (DLS). The loading and release of Ext. from the GO-CS nanocomposite were performed in simulated physiological, and the cytotoxicity of the raw materials (GO and Ext.) and nanocomposites (GO-CS and GO-CS-Ext.) was determined using a human kidney cell line (HEK 293).ResultsThe chemical characterization indicated that the covalent union was successfully achieved between the GO and CS, with 44 wt. % CS in the nanocomposite. The GO-CS nanocomposite was thermostable and presented an average diameter of 480 nm (by DLS). The Ext. loading capacity was approximately 20 wt. %, and under simulated physiological conditions, 28.4 wt.% Ext. (g) was released per g of the nanocomposite. GO-CS-Ext. was noncytotoxic, presenting a 97% survival rate compared with 11% for the raw extract and 48% for the GO-CS nanocomposite at a concentration of 500 µg mL-1 after 24 hrs.ConclusionDue to π–π stacking and hydrophilic interactions, GO-CS was reasonably efficient in binding Ext., with high loading capacity and Ext. release from the nanocomposite. The GO-CS nanocomposite also increased the biocompatibility of PAs-rich Ext., representing a new platform for the sustained release of phytodrugs.

Sensitivity Enhancement of Pb(II) Ion Detection in Rivers Using SPR-Based Ag Metallic Layer Coated with Chitosan-Graphene Oxide Nanocomposite.

The detection of Pb(II) ions in a river using the surface plasmon resonance (SPR)-based silver (Ag) thin film technique was successfully developed. Chitosan–graphene oxide (CS-GO) was coated on top of the Ag thin film surface and acted as the active sensing layer for Pb(II) ion detection. CS-GO was synthesized and characterized, and the physicochemical properties of this material were studied prior to integration with the SPR. In X-ray photoelectron spectroscopy (XPS), the appearance of the C=O, C–O, and O–H functional groups at 531.2 eV and 532.5 eV, respectively, confirms the success of CS-GO nanocomposite synthesis. A higher surface roughness of 31.04 nm was observed under atomic force microscopy (AFM) analysis for Ag/CS-GO thin film. The enhancement in thin film roughness indicates that more adsorption sites are available for Pb(II) ion binding. The SPR performance shows a good sensor sensitivity for Ag/CS-GO with 1.38° ppm−1 ranging from 0.01 to 5.00 ppm of standard Pb(II) solutions. At lower concentrations, a better detection accuracy was shown by SPR using Ag/CS-GO thin film compared to Ag/CS thin film. The SPR performance using Ag/CS-GO thin film was further evaluated with real water samples collected from rivers. The results are in agreement with those of standard Pb(II) ion solution, which were obtained at incidence angles of 80.00° and 81.11° for local and foreign rivers, respectively.

RETRACTED: Statistical and chemometric view of the variation in the concentration of selected organophosphates in peeled unwashed and unpeeled washed fruits and vegetables

Fruits and vegetables play an important role in human nutrition. Study of the contamination sources which result from farming activities is of importance. For this reason, a chitosan-graphene oxide nanocomposite film was prepared and implemented as the extractive phase in thin film microextraction of six organophosphate residues (OPPs) in the samples using high-performance liquid chromatography. The optimized method was validated and the limits of detection (0.7-1.2 µg l-1), limits of quantification (2.3-4.0 µg l-1) and linear dynamic range (2.0-1000.0 µg l-1) were obtained. Principal component analysis revealed clustering of the fruit and vegetable samples based on the selected (OPPs) into two groups of unwashed-unpeeled and peeled-washed. This mapping was further investigated using descriptive method of boxplot. Washing and peeling of the samples, reduced the presence of OPPs to half or one third of interquartile range found in the unpeeled and unwashed samples.

APPLICATIONS OF CHITOSAN–GRAPHENE OXIDE NANOCOMPOSITES IN MEDICAL SCIENCE: A REVIEW

Combinations of biopolymers with nanostructured carbon materials have been the subject of interest of many scientists in recent years. Particularly significant are nanocomposites made of chitosan, which is a linear aminopolysaccharide obtained in the process of deacetylation of chitin, and graphene oxide (GO). These systems, due to the atypical properties of both components such as non-toxicity, biocompatibility with human tissues and organs as well as bacteriostaticity, are characterised by a wide range of biomedical applications. They may be used in emergency medicine as dressing materials which accelerate wound healing, as well as carriers of drugs/genes and biological macromolecules, for example proteins, peptides and nucleic acids. In addition, CS-GO systems can potentially be used in regenerative medicine as scaffolds for cell culture. For this reason, the current publication presents the possibilities of the application of chitosan–graphene oxide nanocomposites in medicine considering the characteristics of the system components.

Synthesis and efficacy of PPy/CS/GO nanocomposites for adsorption of ponceau 4R dye

Polypyrrole/Chitosan/Graphene oxide (PPy/CS/GO) exfoliated nanocomposite was prepared by in-situ polymerization of pyrrole in the presence of intercalated Chitosan/Graphene oxide nanocomposite (CS/GO). The nanocomposites were characterized by thermogravimetric analysis (TGA), Fourier Transform Infrared (FT-IR) spectroscopy, X-ray diffraction, Scanning electron microscope and Transmission electron microscope. The adsorption behavior of PPy/CS/GO was examined using Ponceau 4 R dye (P4R) and the adsorption capacity was compared with GO, CS and CS/GO intercalated nanocomposite. Effect of dye concentration, adsorbent amount, pH, temperature, salt concentration on dye adsorption was studied and adsorbent reproducibility was deliberated. Adsorption of P4R onto PPy/CS/GO nanocomposite was better than CS, GO or CS/GO nanocomposite. The adsorption kinetics of P4R onto PPy/CS/GO nanocomposite could be represented by pseudo-second-order kinetic and the adsorption isotherm obeyed Langmuir isotherm model. Thermodynamic parameters, The Gipps free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were calculated showing that the adsorption of the dye was spontaneous and endothermic.

Waste water treatment by removal of heavy metals using EDTA-functionalized chitosan-graphene oxide nanocomposites

This study focuses on the preparation of Ethylenediaminetetraacetic acid (EDTA)-functionalized magnetic chitosan (CS) graphene oxide (GO) nanocomposites (EDTA-MCS/GO) by biogenic method and its removal efficiency for heavy metals namely, Pb(ll) and As(III) from aqueous solutions. The synthesized nanocomposite was characterized by XRD, SEM, and FTIR analysis. The influence of various operating parameters, such as pH, metal ion concentration, and contact time on the removal of the metal ions, was investigated. The equilibrium data was evaluated by Langmuir, Freundlich and sips isotherms, while the heavy metal adsorption reaction kinetics was analyzed by Lagergren pseudo-first-order and pseudo-second-order kinetic models. The adsorption-desorption studies conducted over 6 cycles illustrate the viability and repeated use of the adsorbent for the removal of Pb(ll)and As(lII) from aqueous solutions.

Cell Growth Inhibition Effect of DsiRNA Vectorised by Pectin-Coated Chitosan-Graphene Oxide Nanocomposites as Potential Therapy for Colon Cancer

Colonic-targeted drug delivery system is widely explored to combat colon-related diseases such as colon cancer. Dicer-substrate small interfering RNA (DsiRNA) has been explored for cancer therapy due to its potency in targeting specific gene of interest. However, its application is limited by rapid degradation and poor cellular uptake. To address this, chitosan-graphene oxide (CS-GO) nanocomposite was used to deliver DsiRNA effectively into cells. Additionally, pectin was used as compatibilization agent to allow specific delivery to the colon and protect the nanocomposites from the harsh environment in the stomach and small intestine. CS-GO-DsiRNA nanocomposites were prepared by electrostatic interaction between CS and GO prior to coating with pectin. The mean particle size of CS-GO-DsiRNA-pectin nanocomposites was 554.5±124.6 nm with PDI and zeta potential of 0.47±0.19 and −10.7±3.0 mV, respectively. TEM analysis revealed smooth and spherical shape of CS-GO-DsiRNA nanocomposites and the shape became irregular after pectin coating. FTIR analysis further confirmed the successful formation of CS-GO-DsiRNA-pectin nanocomposites. Furthermore, the nanocomposites were able to entrap high amount of DsiRNA (% entrapment efficiency of 92.6±3.9%) with strong binding efficiency. CS-GO-DsiRNA-pectin nanocomposites also selectively inhibited cell growth of colon cancer cell line (Caco-2 cells) and were able to decrease VEGF level significantly. In a nutshell, pectin-coated DsiRNA-loaded CS-GO nanocomposites were successfully developed and they have a great potential to deliver DsiRNA to the colon effectively.

Carbon dioxide adsorption and cycloaddition reaction of epoxides using chitosan–graphene oxide nanocomposite as a catalyst

One of today's major challenges is to provide green materials for a cleaner environment. We have conducted studies on carbon dioxide (CO2) adsorption and conversion to valuable products by an ecofriendly approach based in chitosan/graphene oxide (CSGO) nanocomposite film. Rheological behavior indicates that the CSGO has a better solvation property than the pure chitosan. An adsorption capacity of 1.0152mmolCO2/g of CSGO nanocomposite at 4.6bar was observed. The catalytic behavior of the CSGO nanocomposite in the presence of tetra-n-butylammonium iodide (n-Bu4NI) as co-catalyst was evaluated for the cycloaddition of CO2 to epoxides, to give cyclic carbonates, in the absence of any solvent. These results strongly suggest that the CSGO nanocomposite may open new vistas towards the development of ecofriendly material for catalytic conversion and adsorption of CO2 on industrial scale.

Chitosan–graphene oxide nanocomposites: Effect of graphene oxide nanosheets and glycerol plasticizer on thermal and mechanical properties

ABSTRACTIn this study, graphite oxide (GO) is synthesized from natural graphite flakes by the modified Hummers method. Characterization by Fourier transform infrared, X‐ray photoelectron, Raman and ultraviolet‐visible spectroscopies, X‐ray diffraction, and thermogravimetric analysis is conducted on GO to confirm the oxidation of graphite. Unplasticized and glycerol plasticized chitosan/graphene oxide (CS/GO) nanosheets nanocomposites with different GO loadings are prepared by solution casting. The combined effect of GO and glycerol on structure, thermal and mechanical properties of nanocomposite films is studied. GO nanosheets are well dispersed throughout the CS matrix due to the hydrogen bonding and electrostatic interactions between CS and GO nanosheets. The incorporation of GO within the CS matrix results in a decrease of the crystallinity, an improvement of thermal stability, and a significant enhancement of the stiffness and tensile strength that is emphasized by the glycerol. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45092.

Heavy metals removal by EDTA-functionalized chitosan graphene oxide nanocomposites

Graphene-based two-dimensional materials have been explored in a variety of applications, including the treatment of heavy-metal-rich water/wastewater.

Ultrasound assisted mixed azo dye adsorption by chitosan–graphene oxide nanocomposite

Mixed azo dyes present in various effluents may often impair adsorption efficiency thereby questioning applicability of the same in a real-time scenario. In this study, simultaneous adsorption of acid yellow 36 (AY) and acid blue 74 (AB) from their aqueous solutions was carried out with graphene oxide nanoplatelets embedded in chitosan matrix (GO–Cs–Nc) with assistance of ultrasound exposure. Results obtained were subjected to analysis for process isotherms, kinetics and thermodynamics. This process was also optimized for best results using response surface methodology (RSM) and modelled with artificial neural network (ANN). The nanocomposite was characterised both before and after adsorption using FTIR, SEM, TEM and AFM. Under the experimental conditions prescribed by RSM, 0.50gL−1 of adsorbent was responsible for 98.18% and 98.80% removal of AY and AB respectively when exposed to 6.48min of ultrasonic irradiation. Hence, ultrasound assisted GO–Cs–Nc proved to be a cost effective and sustainable adsorbent effective in low dosage and significantly reduced time with possible application for treatment of real industrial effluents rich in mixed dyes.

A ZnO decorated chitosan–graphene oxide nanocomposite shows significantly enhanced antimicrobial activity with ROS generation

The rise in antimicrobial resistance requires the development of new antibacterial agents.

Preparation of Chitosan-Graphene Oxide Nanocomposite and Evaluation of Its Antimicrobial Activity

Preparation of Chitosan-Graphene Oxide Nanocomposite and Evaluation of Its Antimicrobial Activity

Characterisation and drug release performance of biodegradable chitosan–graphene oxide nanocomposites

Biodegradable chitosan–graphene oxide (GO) nanocomposites possess improved mechanical properties and drug delivery performance over chitosan and could prove to be a viable, controlled and pH-sensitive transdermal drug delivery system. Chitosan nanocomposites containing varying GO contents and drug loading ratios were investigated. The nanocomposite with 2wt % GO provided the optimal combination of mechanical properties and drug-loading capacity. It offered a faster and a more substantial release of drug than chitosan as well as a slower biodegradation rate, owing to the abundant oxygenated functional groups, hydrophilicity and large specific surface area of GO sheets. The drug delivery profiles of the nanocomposite were dependent on the drug loading ratio, with 0.84:1 being the best ratio of drug to GO for a quick and high release of the loaded drug. The nanocomposite also demonstrated pH sensitivity of drug release, releasing 48% less drug in an acidic condition than in a neutral environment.

A novel hydrogen peroxide sensor based on Ag nanoparticles electrodeposited on chitosan-graphene oxide/cysteamine-modified gold electrode

A novel strategy to fabricate a hydrogen peroxide sensor based on Ag nanoparticles electrodeposited on chitosan-graphene oxide nanocomposites/cysteamine-modified gold (Au) electrode was reported. The chitosan-graphene oxide nanocomposites were first assembled on a cysteamine-modified Au electrode to produce chitosan-graphene oxide/cysteamine/Au electrode. Then Ag nanoparticles were electrodeposited on the modified Au electrode and formed Ag nanoparticles/chitosan-graphene oxide/cysteamine/Au electrode. The chitosan-graphene oxide nanocomposites and the electrodeposited Ag nanoparticles were characterized by atomic force microscopy and scanning electron microscopy. The results showed the Ag nanoparticles were uniformly dispersed on the chitosan-graphene oxide/cysteamine/Au electrode. The cyclic voltammagrams and amperometric method were used to evaluate electrocatalytic properties of the Ag nanoparticles/chitosan-graphene oxide/cysteamine/Au electrode. The results showed that the modified electrode displayed good electrocatalytic activity to the reduction of hydrogen peroxide with a detection limit of 0.7 μM hydrogen peroxide based on a signal-to-noise ratio of 3. The sensor has good reproducibility, wide linear range, and long-term stability.