Aminated Graphene-Graft-Oligo(Glutamic Acid) /Poly(ε-Caprolactone) Composites: Preparation, Characterization and Biological Evaluation

Abstract

Biodegradable and biocompatible composites are of great interest as biomedical materials for various regeneration processes such as the regeneration of bones, cartilage and soft tissues. Modification of the filler surface can improve its compatibility with the polymer matrix, and, as a result, the characteristics and properties of composite materials. This work is devoted to the synthesis and modification of aminated graphene with oligomers of glutamic acid and their use for the preparation of composite materials based on poly(ε-caprolactone). Ring-opening polymerization of N-carboxyanhydride of glutamic acid γ-benzyl ester was used to graft oligomers of glutamic acid from the surface of aminated graphene. The success of the modification was confirmed by Fourier-transform infrared and X-ray photoelectron spectroscopy as well as thermogravimetric analysis. In addition, the dispersions of neat and modified aminated graphene were analyzed by dynamic and electrophoretic light scattering to monitor changes in the characteristics due to modification. The poly(ε-caprolactone) films filled with neat and modified aminated graphene were manufactured and carefully characterized for their mechanical and biological properties. Grafting of glutamic acid oligomers from the surface of aminated graphene improved the distribution of the filler in the polymer matrix that, in turn, positively affected the mechanical properties of composite materials in comparison to ones containing the unmodified filler. Moreover, the modification improved the biocompatibility of the filler with human MG-63 osteoblast-like cells.

Enhanced Photostability and Photoactivity of Ruthenium Polypyridyl-Based Photocatalysts by Covalently Anchoring Onto Reduced Graphene Oxide

“…The thermal stability of the materials was determined by TGA ( Figure S8 ), with both Ru-anchored materials exhibiting slightly higher thermal stabilities at >500 °C compared to the bare rGO, in line with other rGO-based composites reported in the literature. 55 − 57 Furthermore, PXRDs of the hybrid materials and bare rGO presented consistently two main peaks at ca. 27 and 43°, attributed to the (002) and (101) reflections.…”

Graphene Amination towards Its Grafting by Antibodies for Biosensing Applications

“…To further assess the composition of the introduced nitrogen groups, the N 1s spectrum of the rGO-Am layer was examined after the deconvolution (Figure 1b). Four peaks were discerned centered at BEs of 398.7 eV, 400.1 eV, 401.3 eV and 403.5 eV, which matured from the presence of pyridines, amines, embedded graphitic nitrogen and pyridine-Noxide moieties, respectively [33,34]. The relative concentrations of these nitrogen groups estimated by comparing the relative integral intensity are calculated to be 17.34%, 74.47%, 5.52% and 2.67%, respectively.…”

“…Even more drastic changes are seen from the C 1s spectra presented in Figure 1c. Upon the immobilization procedure, the oxygen-related peaks centered at BEs of 286.9 eV, 288.2 eV and 289.1 eV increase, originating from the presence of the C-OH&C-O-C, C=O and COOH groups, respectively [33,41,42], and completely absent in the rGO-Am C 1s spectrum due to the elimination of these oxygen moieties during amination. The concentration of these oxygen groups enhances from 4.23 at.%, 0.97 at.% and 1.48 at.% to 24.90 at.%, 12.70 at.% and 1.5 at.%, respectively, as seen from the quantitative data derived from processing the deconvoluted C 1s spectra and summarized in Table 1.…”

Graphene for Antimicrobial and Coating Application

“…Finally, biodegradable composites have been used in various regeneration processes applications such as the regeneration of bones, cartilage, and soft tissues. Stepanova et al [ 90 ] synthesized aminated graphene with oligomers of glutamic acid and their use for the preparation of composite materials based on poly(ε-caprolactone) for tissue regeneration applications. The poly(ε-caprolactone) films filled with modified aminated graphene were produced and characterized for their mechanical and biological properties.…”