ABSTRACT
The present work aims to develop new biocomposites based on gelatin (Gel) and poly(vinyl alcohol) (PVA) reinforced with graphene oxide (GO). On the one hand, the model is designed with consideration of the high performance of the aforementioned biopolymers as biomaterials; on the other hand, the original component of the system, GO, is expected to improve structural stability and boost mechanical strength. Porous Gel-PVA/GO materials with GO content ranging from 0.5 to 3 wt% are obtained by freeze-drying. Structural analysis by Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the ability of well-dispersed GO nanosheets to form interactions with the polymers, leading to a unique molecular structuration. 3D analysis by X-ray microtomography (microCT) and scanning electron microscopy (SEM) suggests that GO has an influence on pore adjustment. According to mechanical tests, GO undoubtedly exhibits a beneficial effect on the polymer resistance against compressive stress, improving their compressive strengths by 97-100% with the addition of 0.5-3 wt% GO. Moreover, biological assessment using the MC3T3-E1 preosteoblast murine cell line indicated the fabrication of a cytocompatible composite formula, with potential for further in vivo testing and tissue engineering applications.
ABSTRACT
Gold-dendrimer nanocomposites were obtained for the first time by a simple colloidal approach based on the use of polyamidoamine dendrimers with succinamic acid terminal groups and dodecanediamine core. Spherical and highly crystalline nanoparticles with dimensions between 3 nm and 60 nm, and size-polydispersity depending on the synthesis conditions, have been generated. The influence of the stoichiometric ratio and the structural and architectural features of the dendrimers on the properties of the nanocomposites has been described. The self-assembling behaviour of these materials produces gold-dendrimer nanostructured porous networks with variable density, porosity, and composition. The investigations of the reaction systems, by TEM, at two postsynthesis moments, allowed to preliminary establish the control over the properties of the nanocomposite products. Furthermore, this study allowed better understanding of the mechanism of nanocomposite generation. Impressively, in the early stages of the synthesis, the organization of gold inside the dendrimer molecules has been evidenced by micrographs. Growth and ripening mechanisms further lead to nanoparticles with typical characteristics. The potential of such nanocomposite particles to induce calcification when coating a polymer substrate was also investigated.