Graphene oxide/multi-walled carbon nanotubes as nanofeatured scaffolds for the assisted deposition of nanohydroxyapatite: characterization and biological evaluation

Author(s)

Rodrigues, Bruno V. M. ; Leite, Nelly C. S. ; Cavalcanti, Bruno das Neves ; da Silva, Newton S. ; Marciano, Fernanda R. ; Corat, Evaldo J. ; Webster, Thomas J. ; Lobo, Anderson O.

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF NANOMEDICINE; v. 11, p. 17-pg., 2016-01-01.

Abstract

Nanohydroxyapatite (nHAp) is an emergent bioceramic that shows similar chemical and crystallographic properties as the mineral phase present in bone. However, nHAp presents low fracture toughness and tensile strength, limiting its application in bone tissue engineering. Conversely, multi-walled carbon nanotubes (MWCNTs) have been widely used for composite applications due to their excellent mechanical and physicochemical properties, although their hydrophobicity usually impairs some applications. To improve MWCNT wettability, oxygen plasma etching has been applied to promote MWCNT exfoliation and oxidation and to produce graphene oxide (GO) at the end of the tips. Here, we prepared a series of nHAp/MWCNT-GO nanocomposites aimed at producing materials that combine similar bone characteristics (nHAp) with high mechanical strength (MWCNT-GO). After MWCNT production and functionalization to produce MWCNT-GO, ultrasonic irradiation was employed to precipitate nHAp onto the MWCNT-GO scaffolds (at 1-3 wt%). We employed various techniques to characterize the nanocomposites, including transmission electron microscopy (TEM), Raman spectroscopy, thermogravimetry, and gas adsorption (the Brunauer-Emmett-Teller method). We used simulated body fluid to evaluate their bioactivity and human osteoblasts (bone-forming cells) to evaluate cytocompatibility. We also investigated their bactericidal effect against Staphylococcus aureus and Escherichia coli. TEM analysis revealed homogeneous distributions of nHAp crystal grains along the MWCNT-GO surfaces. All nanocomposites were proved to be bioactive, since carbonated nHAp was found after 21 days in simulated body fluid. All nanocomposites showed potential for biomedical applications with no cytotoxicity toward osteoblasts and impressively demonstrated a bactericidal effect without the use of antibiotics. All of the aforementioned properties make these materials very attractive for bone tissue engineering applications, either as a matrix or as a reinforcement material for numerous polymeric nanocomposites. (AU)

• FAPESP's process: 15/08523-8 - Development of a fluorescent nanosensor from the electrospinning of PVA and graphene quantum dots: application in the detection of Alzheimer's biomarkers
• Grantee: Bruno Vinícius Manzolli Rodrigues
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 11/20345-7 - Study of nanoparticle-incorporated diamond-like carbon films for biomedical applications
• Grantee: Fernanda Roberta Marciano
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 13/20054-8 - Studies of adhesion, proliferation and cell death in the interaction of cells with nanostructured materials
• Grantee: Newton Soares da Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/17877-7 - Development of new polymeric scaffolds by electrospinning technique with incorporation of vertically aligned carbon nanotubes and nanohidroxyapatite for bone tissue regeneration
• Grantee: Anderson de Oliveira Lobo
• Support Opportunities: Research Grants - Young Investigators Grants