Effect of graphene oxide incorporation into polymeric matrix of polysaccharide multilayered microcapsules (2025)

Polysaccharide nanocomposites reinforced with graphene oxide and keratin-grafted graphene oxide

2012

Nanocomposites of polysaccharide matrices, chitosan−starch, and carboxymethyl cellulose-starch reinforced with graphene oxide and graphene grafted with keratin were developed. Composites films had been prepared for the casting/solvent evaporation method. The interaction and distribution of graphene materials in the biopolymer matrices were analyzed by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM), and the thermomechanical properties were examined using dynamic mechanical analysis. The nanocomposites of the chitosan−starch matrix improved their mechanical properties substantially, with respect to the film without reinforcing, obtaining an increase of 929% in the storage modulus (E′, 35°C) with only 0.5 wt % of graphene oxide and outstanding increments in E′ at 150 and 200°C when keratin-grafted graphene oxide is incorporated (0.1 wt %). In contrast, the graphene oxide incorporated into the carboxymethyl cellulose−starch matrix tends to decrease the stiffness of the film, behaving in a manner opposite to that of nanocomposites of the chitosan−starch matrix. Similarly, the incorporation of graphene grafted with keratin shows a decrease in the rigidity of the resulting material. In this way, the importance of compatibility between the graphene and the host matrix to achieve a fine control of interface and manipulate the final properties of the material is demonstrated.

Robust microcapsules with controlled permeability from silk fibroin reinforced with graphene oxide

Small (Weinheim an der Bergstrasse, Germany), 2014

Robust and stable microcapsules are assembled from poly-amino acid-modified silk fibroin reinforced with graphene oxide flakes using layer-by-layer (LbL) assembly, based on biocompatible natural protein and carbon nanosheets. The composite microcapsules are extremely stable in acidic (pH 2.0) and basic (pH 11.5) conditions, accompanied with pH-triggered permeability, which facilitates the controllable encapsulation and release of macromolecules. Furthermore, the graphene oxide incorporated into ultrathin LbL shells induces greatly reinforced mechanical properties, with an elastic modulus which is two orders of magnitude higher than the typical values of original silk LbL shells and shows a significant, three-fold reduction in pore size. Such strong nanocomposite microcapsules can provide solid protection of encapsulated cargo under harsh conditions, indicating a promising candidate with controllable loading/unloading for drug delivery, reinforcement, and bioengineering applications.

Hybrid graphene oxide/polysaccharide nanocomposites with controllable surface properties and biocompatibility

Carbohydrate Polymers, 2018

Herein, a strong interdependence between the composition of hybrid graphene oxide/hyaluronan/chitosan GO/HA/Chi multilayers and their surface properties and biocompatibility was demonstrated that can be used to build up coatings with desirable and precisely tunable properties. Both the position and the abundance of GO-layers into the polymer matrix were systematically varied to draw interconnection with the growth type, thickness, morphology, roughness, hydrophilicity and biocompatibility. It was found that when deposited in-between the HA and Chi layers GO forms diffusion barrier, hindering the mobility of Chi-chains and changing the exponential film growth to linear. Incorporation of GO-layers into the biodegradable and highly hydrated HA/Chi matrix does not affect the final thickness, but has a dramatic impact on the surface morphology and roughness, which in turn tunes the hydrophilicity, protein adsorption and platelets adhesion. This provides an opportunity for various biomedical applications of the studied hybrid films as coatings with controllable surface properties.

Hierarchically aligned fibrous hydrogel films through microfluidic self‐assembly of graphene and polysaccharides

Biotechnology and Bioengineering, 2018

Poly(ε-caprolactone)/graphene oxide biocomposites: mechanical properties and bioactivity Poly(ε-caprolactone)/graphene oxide biocomposites: mechanical properties and bioactivity

Biomedical applications of graphene have recently attracted intensive attention, with graphene-based nanomaterials being reported as promising candidates in, for example, drug delivery, biosensing and bioimaging. In this paper, mechanical properties and bioactivity of nanofibrous and porous membranes electrospun from graphene oxide (GO) nanoplatelets reinforced poly(ε-caprolactone) (PCL) were investigated. The results showed that the presence of 0.3 wt% GO increased the tensile strength, modulus and energy at break of the PCL membrane by 95%, 66% and 416%, respectively, while improving its bioactivity during biomineralization and maintaining the high porosity of over 94%. The mechanical enhancements were ascribed to the change in the fiber morphology and the reinforcing effect of GO on PCL nanofibers, whereas the improvements on the bioactivity stemmed from the anionic functional groups present on the GO surface that nucleated the formation of biominerals. Systematic studies on the PCL/GO nanocomposite films with varying GO concentrations revealed that the reinforcing effect of GO on PCL was due to the strong interfacial interactions between the two phases characterized by Fourier transform infrared spectroscopy, the good dispersion of GO in the matrix and the intrinsic properties of GO nanoplatelets. The strong and bioactive PCL/GO nanofibrous membranes with a high porosity have great potential for biomedical applications.

Starch-graphene oxide bionanocomposites prepared through melt mixing

Journal of Applied Polymer Science, 2017

Bionanocomposites (BNCs) of waxy corn starch, glycerol, and graphene oxide (GO) or graphite oxide (GrO) were prepared by melt mixing. First, the GrO was pre-exfoliated in a water solution using ultrasound at 1 wt %. Small-angle X-ray scattering was used to determinate the interlaminar separation of GrO and transmission electron microscopy, Fourier infrared spectroscopy, and thermogravimetric analysis were used to characterized the GrO. Next, BNCs were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and mechanical property measurements. A complete exfoliation of GrO was obtained in the waxy corn matrix. Amorphous X-ray patterns of the BNCs were observed, indicating that the exfoliated GO avoid the retrogradation of starch. According to scanning electron microscopy results, the BNCs showed an irregular texture and a good dispersion of GO, while thermoplastic starch showed a smooth morphology with a fragile structure. The BNCs exhibited higher thermal stability than thermoplastic starch. The tensile strength and the Young's modulus increased by 140% and 230% at a GO loading levels of 0.5% due to good interfacial interactions of GO and the waxy corn starch matrix.

Functionalized graphene and graphene oxide solution via polyacrylate coating

Nanoscale, 2010

Smart microcapsules containing nonpolar chemical compounds and carbon nanofibers

Chemical Engineering Journal, 2012

Thermoresponsive graphene oxide – starch micro/nanohydrogel composite as biocompatible drug delivery system

BioImpacts

Introduction: Stimuli-responsive hydrogels, which indicate a significant response to the environmental change (e.g., pH, temperature, light, …), have potential applications for tissue engineering, drug delivery systems, cell therapy, artificial muscles, biosensors, etc. Among the temperature-responsive materials, poly (N-isopropylacrylamide) (PNIPAAm) based hydrogels have been widely developed and their properties can be easily tailored by manipulating the properties of the hydrogel and the composite material. Graphene oxide (GO), as a multifunctional and biocompatible nanosheet, can efficiently improve the mechanical strength and response rate of PNIPAAmbased hydrogels. Here, hydrogel composites (HCs) of PNIPAAm with GO was developed using the modified starch as a biodegradable cross-linker. Methods: Micro/nanohydrogel composites were synthesized by free radical polymerization of NIPAAm in the suspension of different feed ratio of GO using maleate-modified starch (St-MA) as cross-linker and Tetrakis (hydroxymethyl) phosphonium chloride (THPC) as a strong oxygen scavenger. The HCs were characterized by FT-IR, DSC, TGA, SEM, and DLS. Also, the phase transition, swelling/deswelling behavior, hemocompatibility and biocompatibility of the synthesized HCs were investigated. Results: The thermal stability, phase transition temperature and internal network crosslinking of HCs increases with increasing of the GO feed ratio. Also, the swelling/deswelling, hemolysis, and MTT assays studies confirmed that the HCs are a fast response, hemocompatible and biocompatible materials. Conclusion: The employed facile approach for the synthesis of HCs yields an intelligent material with great potential for biomedical applications.

GRAPHENE OXIDE MICROCAPSULES (GOMs) WITH LINSEED OIL CORE VIA PICKERING EMULSION METHOD: EFFECT OF DISPERSE SPEED

IIUM Engineering Journal

Graphene oxide microcapsules (GOMs) have been prepared through Pickering emulsion method by varying the disperse speed to study its effect on the GOM’s size. The GOMs were characterized through phase separation observation, polarized optical microscope (POM), and particle size analyser (PSA). Phase separation observation showed more viscous and cloudy emulsion was produced when the disperse speed was increased. After 24 hours, only 800 rpm emulsion did not show any phase separation. POM characterization depicted that increasing the emulsification energy led to the finer emulsion with the 1200 rpm sample showing the smallest microcapsule size of around 8 ?m. However, PSA analysis suggested that although the disperse speed controls the GOMs size, the amount of GO in the emulsion plays an important role for the microcapsule to maintain its stability. Emulsion produced at 800 rpm possesses satisfactory stability with GOMs diameter of 11.15 ?m. The result also suggested that graphene oxi...