Three‐dimensional macroporous graphene scaffolds for tissue engineering

Abstract

The assembly of carbon nanomaterials into three-dimensional (3D) porous scaffolds is critical to harness their unique physiochemical properties for tissue engineering and regenerative medicine applications. In this study, we report the fabrication, characterization, and in vitro cytocompatibility of true 3D (>1 mm in all three dimensions), macroscopic (3-8 mm in height and 4-6 mm in diameter), chemically cross-linked graphene scaffolds prepared via radical initiated thermal cross-linking of single- and multiwalled graphene oxide nanoribbons (SWGONRs and MWGONRs). SWGONR and MWGONR scaffolds possess tunable porosity (∼65-80%) and interconnected macro-, micro-, and nanoscale pores. Human adipose derived stem cells (ADSCs) and murine MC3T3 preosteoblast cells show good cell viability on SWGONR and MWGONR scaffolds after 1, 3, and 5 days comparable to 3D poly(lactic-co-glycolic) acid (PLGA) scaffolds. Confocal live-cell imaging showed that cells were metabolically active and could spread on SWGONR and MWGONR scaffolds. Immunofluorescence imaging showed the presence of focal adhesion protein vinculin and expression of cell proliferation marker Ki-67 suggesting that cells could attach and proliferate on SWGONR and MWGONR scaffolds. These results indicate that cross-linked SWGONR and MWGONR scaffolds are cytocompatible and opens-avenues toward the development of 3D multifunctional graphene scaffolds for tissue engineering applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 73-83, 2017.

Toxicology of graphene-based nanomaterials

“…Therefore, more studies assessing the long-term environmental impact of graphene are required. Recent efforts have also involved incorporation of graphene nanoparticles in polymer matrices or their assembly in coating, films and porous scaffolds for bio-sensing, localized drug delivery or tissue engineering applications [147, 148]. For these applications, additional in vitro and in vivo toxicological studies specific to biomedical devices and implants would be needed.…”

Two‐dimensional graphene oxide‐reinforced porous biodegradable polymeric nanocomposites for bone tissue engineering

“…Furthermore, cells were metabolically active and the formation of filopodia and cellular extensions (Figure d, white arrows) extending outward from the cell body (black circles) was observed. It is critical for cells to attach and infiltrate the porous scaffolds and initiate the deposition of ECM proteins for effective new tissue regeneration . Collagen‐I protein acts as a binder to facilitate the attachment of cells with scaffolds and other ECM components thereby playing an essential role in cellular signaling, differentiation and tissue maturation .…”

“…Protein adsorption on scaffolds is essential for cellular adhesion and ECM deposition. [43][44][45] Here, we have assessed the adsorption of collagen-I protein (Figure 4) using a wellaccepted protein solution depletion method 24 employing bicinchoninic acid assay. 46 Collagen-I is the principal constituent of the ECM.…”

Three‐dimensional carbon nanotube scaffolds for long‐term maintenance and expansion of human mesenchymal stem cells

“…Optical images of 3‐D MWCNT, SWCNT, and PLGA scaffolds are shown in Figure (A). We have previously reported the use of BP as a radical initiator to induce thermal cross‐linking of CNTs and graphene toward the fabrication of 3‐D all‐carbon architectures . BP decomposes into benzoyl and benzoyloxyl free radicals that attack the CC sp 2 bonds on CNT structure forming active centers that serve as inter nanotube cross‐linking sites.…”

“…We have previously reported the use of BP as a radical initiator to induce thermal cross-linking of CNTs and graphene toward the fabrication of 3-D all-carbon architectures. 40,51 BP decomposes into benzoyl and benzoyloxyl free radicals that attack the C@C sp 2 bonds on CNT structure forming active centers that serve as inter nanotube crosslinking sites. Unreacted BP and other volatile compounds are removed by thermal annealing (1508C for 30 min), which results in the partial restoration of the sp 2 bonds.…”