PDLLA honeycomb-like scaffolds with a high loading of superhydrophilic graphene/multi-walled carbon nanotubes promote osteoblast in vitro functions and guided in vivo bone regeneration

• Published in: Materials Science & Engineering C Vol. 73; pp. 31 - 39
• Main Authors: Silva, Edmundo, Vasconcellos, Luana Marotta Reis de, Rodrigues, Bruno V.M., dos Santos, Danilo Martins, Campana-Filho, Sergio P., Marciano, Fernanda Roberta, Webster, Thomas J., Lobo, Anderson Oliveira
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2017; Elsevier BV
• Subjects: Adhesion tests; Adhesive strength; Alkaline phosphatase; Animals; Biocompatibility; Biological Assay; Biomedical materials; Bone and Bones - drug effects; Bone and Bones - pathology; Bone growth; Bone Regeneration - drug effects; Carbon; Cell adhesion; Cell interactions; Cell Line; Cell Survival - drug effects; Cytotoxicity; Differentiation; Elongation; Etching; Fillers; Graphene; Graphene oxide; Graphite - pharmacology; Guided Tissue Regeneration; Honeycomb construction; Humans; Hydrophobic and Hydrophilic Interactions; In vivo evaluation; In vivo methods and tests; Lactic acid; Loading; Male; Materials science; Materials Testing; Mechanical properties; Multi wall carbon nanotubes; Multi-walled carbon nanotubes; Nanotechnology; Nanotubes; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Nodules; Orthopedics; Osteoblastogenesis; Osteoblasts - cytology; Osteoblasts - drug effects; Osteogenesis; Oxidation; Oxides; Oxygen plasma; Plasma etching; Poly (d, l-lactic acid); Polyesters - chemistry; Polyesters - pharmacology; Prosthesis Implantation; Rats; Regeneration; Regeneration (physiology); Stereoisomerism; Stress, Mechanical; Tensile Strength; Tibia; Tissue Scaffolds - chemistry; Alkaline phosphatase; Graphene oxide; Multi-walled carbon nanotubes; Poly (d, l-lactic acid); Orthopedics; In vivo evaluation
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2016.11.075

Herein, we developed honeycomb-like scaffolds by combining poly (d, l-lactic acid) (PDLLA) with a high amount of graphene/multi-walled carbon nanotube oxides (MWCNTO-GO, 50% w/w). From pristine multi-walled carbon nanotubes (MWCNT) powders, we produced MWCNTO-GO via oxygen plasma etching (OPE), which promoted their exfoliation and oxidation. Initially, we evaluated PDLLA and PDLLA/MWCNTO-GO scaffolds for tensile strength tests, cell adhesion and cell viability (with osteoblast-like MG-63 cells), alkaline phosphatase (ALP, a marker of osteoblast differentiation) activity and mineralized nodule formation. In vivo tests were carried out using PDLLA and PDLLA/MWCNTO-GO scaffolds as fillers for critical defects in the tibia of rats. MWCNTO-GO loading was responsible for decreasing the tensile strength and elongation-at-break of PDLLA scaffolds, although the high mechanical performance observed (~600MPa) assures their application in bone tissue regeneration. In vitro results showed that the scaffolds were not cytotoxic and allowed for osteoblast-like cell interactions and the formation of mineralized matrix nodules. Furthermore, MG-63 cells grown on PDLLA/MWCNTO-GO significantly enhanced osteoblast ALP activity compared to controls (cells alone), while the PDLLA group showed similar ALP activity when compared to controls and PDLLA/MWCNTO-GO. Most impressively, in vivo tests suggested that compared to PDLLA scaffolds, PDLLA/MWCNTO-GO had a superior influence on bone cell activity, promoting greater new bone formation. In summary, the results of this study highlighted that this novel scaffold (MWCNTO-GO, 50% w/w) is a promising alternative for bone tissue regeneration and, thus, should be further studied. [Display omitted] •Honeycomb-like scaffolds were produced by combining PDLLA with graphene/multi-walled carbon nanotube oxides (MWCNTO-GO)•MWCNTO-GO loading was responsible for decreasing the tensile strength and elongation-at-break of PDLLA scaffolds•The scaffolds enhanced osteoblast ALP activity and promoted greater new bone formation.