Biomimetic Mineralized Hierarchical Graphene Oxide/Chitosan Scaffolds with Adsorbability for Immobilization of Nanoparticles for Biomedical Applications

Abstract

Biomimetic calcium phosphate mineralized graphene oxide/chitosan (GO/CS) scaffolds with hierarchical structures were developed. First, GO/CS scaffolds with large micropores (∼300 μm) showed high mechanical strength due to the electrostatic interaction between the oxygen-containing functional groups of GO and the amine groups of CS. Second, octacalcuim phosphate (OCP) with porous structures (∼1 μm) was biomimetically mineralized on the surfaces of the GO/CS scaffolds (OCP-GO/CS). The hierarchical microporous structures of OCP-GO/CS scaffolds provide a suitable environment for cell adhesion and growth. The scaffolds have exceptional adsorbability of nanoparticles. Bone morphogenetic protein-2 (BMP-2)-encapsulated bovine serum albumin (BSA) nanoparticles and Ag nanoparticles (Ag-NPs) were adsorbed in the scaffolds for enhancement of osteoinductivity and antibacterial properties, respectively. Antibacterial tests showed that the scaffolds exhibited high antibacterial properties against both Escherichia coli and Staphylococcus epidermidis. In vitro and in vivo experiments revealed that the scaffolds have good biocompatibility, enhanced bone marrow stromal cells proliferation and differentiation, and induced bone tissue regeneration. Thus, the biomimetic OCP-GO/CS scaffolds with immobilized growth factors and antibacterial agents might be excellent candidates for bone tissue engineering.

Graphene oxide nanolayers as nanoparticle anchors on biomaterial surfaces with nanostructures and charge balance for bone regeneration

“…The BMP‐2 encapsulation ratio of NP was 96.3 ± 2.5%. NPs exhibited a high BMP‐2 encapsulation ratio because BMP‐2 was directly encapsulated into BSA, and then BSA was further stabilized by CS . These results indicate that the negative charged GO can immobilize the positive charged NPs by electrostatic interaction.…”

“…BMP‐encapsulated BSA‐NPs were prepared using a desolvation method . First, 1 mg of BMP‐2 (Rebon, China) was dissolved in 20 mL of 50 mg mL −1 bovine serum albumin (BSA; Sigma) solution.…”

“…The adsorption ratios of NPs on the GO‐HA and GO‐TCP scaffolds were determined by the following equation: where Q is the adsorption ratio, C 0 and C 1 are the initial and residual concentrations of NPs, respectively.…”

Novel biomaterial strategies for controlled growth factor delivery for biomedical applications

“…Our research also confirmed that chitosan-decorated BMP-2-encapsulated (BSA) NPs immobilized on graphene oxide/chitosan scaffolds significantly enhanced bone marrow stromal cell functions and induced bone tissue regeneration. 72 Polysaccharide-based NPs Polysaccharides are comprised of multiple monosaccharide units joined together by glycosidic linkages (Figure 3c). 73 Polysaccharides are the most attractive and promising natural polymers for the preparation of drug-encapsulated NPs due to their abundance in nature, low toxicity, high stability, low cost, biocompatibility, and presence of various functional groups on molecular chains.…”

Electroresponsive and cell-affinitive polydopamine/polypyrrole composite microcapsules with a dual-function of on-demand drug delivery and cell stimulation for electrical therapy

“…The surgery was performed as previously reported. 24 After 4 weeks of implantation, all samples were harvested for methylene blue and basic fuchsin staining and then observed using a light microscope (BX63, Olympus, Tokyo, Japan). Detailed experimental processes are provided in the Supplementary Information.…”