Biomedical films of graphene nanoribbons and nanoflakes with natural polymers

Abstract

Graphene and its derivatives are promising as reinforcement for polymer nanocomposites. Additionally to their inherent outstanding mechanical properties, these nanoparticles may be functionalized to enhance their compatibility with the polymeric matrix and provide specific chemical and physical properties. In this work, new freestanding films (FS) based on chitosan (CHI), alginate (ALG) and functionalized graphene were developed using the layer-by-layer assembly. Suspensions of functionalized graphene nanoflakes (f-GF) and nanoribbons (f-GNR) were prepared from expanded graphite (EG) and multiwalled carbon nanotubes (MWNTs), respectively. The graphene nanoflakes and MWNTs were covalently functionalized using a 1,3-dipolar cycloaddition reaction that allowed the nanoparticles exfoliation. f-GNR and f-GF suspensions were characterized to demonstrate that graphene nanoflakes and MWNTs were successfully functionalized and exfoliated. Then, the layer-by-layer deposition of CHI, ALG and both types of functionalized graphene was investigated and FS films were produced. The morphology, thermal and mechanical characteristics of the produced FS films were assessed. Their degradation and swelling profiles as well as their biological behavior were evaluated. The incorporation of f-GF resulted in smoother films while the incorporation of f-GNR resulted in rougher films. When compared with the CHI/ALG bi-component films. Both graphene containing films remained hydrophobic. The graphene incorporation in the multilayered FS was estimated to be 1.7 wt% for f-GF and 2.5 wt% for f-GNR. The presence of functionalized graphene did not affect the thermal stability of the films, it increased the storage modulus and the dynamic mechanical response at 1 Hz and 37 C, and decreased the electrical resistivity. The biological assays revealed cytocompatibility towards L929 cells when both f-GF and f-GNR were incorporated in the CHI/ALG matrix. In conclusion, these new f-GF and f-GNR reinforced FS films present great potential for use in biomedical applications such as films for wound healing or cardiac and bone engineering.

<p>Applications of Graphene and Its Derivatives in Bone Repair: Advantages for Promoting Bone Formation and Providing Real-Time Detection, Challenges and Future Prospects</p>

“…Moreover, GO could be functionalized to further improve its electrical conductivity. 94,95 For example, Jin et al 94 introduced GO into the polyvinyl chloride/poly(lactic-co-glycolic acid) (PVC/PLGA) scaffold by electrospinning, and then GO-PVC/PLGA 96 composite scaffolds were immersed in hydrogen iodide solution to obtain rGO-PVC/PLGA scaffolds. The results showed that compared with GO-PVC/PLGA scaffolds, rGO-PVC/PLGA scaffolds had higher capacitance and better conductivity at a suitable voltage, which was due to the larger SSA of rGO-PVC/PLGA and the formation of more conjugated π-bonds on the surface of rGO.…”

“…The results showed that compared with GO-PVC/PLGA scaffolds, rGO-PVC/PLGA scaffolds had higher capacitance and better conductivity at a suitable voltage, which was due to the larger SSA of rGO-PVC/PLGA and the formation of more conjugated π-bonds on the surface of rGO. In another case, Silva et al 95 introduced cyclic amine into graphene by 1.3-dipolar cycloaddition reaction, and then functionalized graphene was compounded with chitosan (CHI) and sodium alginate (ALG) to fabricate biofilms. The results showed that the introduction of functionalized graphene significantly reduced the resistivity of the thin films from 3.00 × 10 12 Ω m to 2.25 × 10 9 Ω m.…”

An Overview of Functionalized Graphene Nanomaterials for Advanced Applications

“…Some useful features of such materials include biodegradability, low toxicity, and gel-forming ability, as well as reasonably low preparation costs. For instance, Silva et al [ 155 ] covalently functionalized graphene with N -benzyloxycarbonylglycine (Z-Gly-OH), in order to produce films through layer-by-layer deposition of chitosan and alginate chitosan. They found that the obtained films, beyond being cytocompatible, exhibited enhanced mechanical and electrical performance in comparison to the same systems without the functionalized graphene.…”

“…They found that the obtained films, beyond being cytocompatible, exhibited enhanced mechanical and electrical performance in comparison to the same systems without the functionalized graphene. These results suggest good potential for biomedical applications such as wound healing and regenerative medicine [ 155 ].…”

Effect of different functionalized carbon nanostructures as fillers on the physical properties of biocompatible poly(l-lactic acid) composites

“…Composites of CNSs and biocompatible polymers can combine the properties of the two constituents and act as functional materials for a number of technological applications, [7,8] which include medical devices and implants [9][10][11][12], tissue engineering [13][14][15][16][17][18][19][20][21][22][23][24], drug delivery [25,26], bio-, green and wearable electronics [27][28][29], biosensing [29][30][31][32][33][34], soft robotics [35,36] and smart packaging [37][38][39].…”