Article

Two-Dimensional Nanostructure-Reinforced Biodegradable Polymeric Nanocomposites for Bone Tissue Engineering

Department of Biomedical Engineering, Stony Brook University , Stony Brook, New York 11794-5281, United States.
Biomacromolecules (Impact Factor: 5.79). 02/2013; 14(3). DOI: 10.1021/bm301995s
Source: PubMed

ABSTRACT This study investigates the efficacy of two-dimensional (2D) carbon and inorganic nanostructures as reinforcing agents for cross-linked composites of the biodegradable and biocompatible polymer polypropylene fumarate (PPF) as a function of nanostructure concentration. PPF composites were reinforced using various 2D nanostructures: single- and multiwalled graphene oxide nanoribbons (SWGONRs, MWGONRs), graphene oxide nanoplatelets (GONPs), and molybdenum disulfide nanoplatelets (MSNPs) at 0.01-0.2 weight% concentrations. Cross-linked PPF was used as the baseline control, and PPF composites reinforced with single- or multiwalled carbon nanotubes (SWCNTs, MWCNTs) were used as positive controls. Compression and flexural testing show a significant enhancement (i.e., compressive modulus = 35-108%, compressive yield strength = 26-93%, flexural modulus = 15-53%, and flexural yield strength = 101-262% greater than the baseline control) in the mechanical properties of the 2D-reinforced PPF nanocomposites. MSNP nanocomposites consistently showed the highest values among the experimental or control groups in all the mechanical measurements. In general, the inorganic nanoparticle MSNP showed a better or equivalent mechanical reinforcement compared to carbon nanomaterials, and 2D nanostructures (GONPs, MSNPs) are better reinforcing agents compared to one-dimensional (1D) nanostructures (e.g., SWCNTs). The results also indicated that the extent of mechanical reinforcement is closely dependent on the nanostructure morphology and follows the trend nanoplatelets > nanoribbons > nanotubes. Transmission electron microscopy of the cross-linked nanocomposites indicated good dispersion of nanomaterials in the polymer matrix without the use of a surfactant. The sol-fraction analysis showed significant changes in the polymer cross-linking in the presence of MSNP (0.01-0.2 wt %) and higher loading concentrations of GONP and MWGONR (0.1-0.2 wt %). The analysis of surface area and aspect ratio of the nanostructures taken together with the above results indicated differences in nanostructure architecture (2D vs 1D nanostructures), and the chemical compositions (inorganic vs carbon nanostructures), number of functional groups, and structural defects for the 2D nanostructures may be key properties that affect the mechanical properties of 2D nanostructure-reinforced PPF nanocomposites and the reason for the enhanced mechanical properties compared to the controls.

4 Followers
 · 
806 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The musculoskeletal tissues are highly ordered nanostructured materials, and they have self-healing capability. However, when the tissue damage is beyond the capability, therapeutic approaches to repair or regenerate the tissues are needed. Nanomaterials have attracted much research attention to create novel tissue engineering scaffolds, because of their small size, large surface area, enhanced mechanical properties, tunable molecular and chemical structures, and various surface functionalities. With the development of nanotechnology, nanostructured materials with properties that more closely fulfill the requirement in the course of recovery of native tissues were designed, synthesized, characterized and utilized systematically. Here, we introduced the microenvironment of extracellular matrix in musculoskeletal tissues. We further summarized the current nanostructured materials used in musculoskeletal tissue engineering including natural polymers, synthetic polymers and inorganic materials. Specifically, the fabrications and applications of different nanomaterials in bone, cartilage, and muscle tissue engineering were discussed in details. The most recent research achievement in each category were presented and discussed. Overall, nanostructured materials can be synthesized with controlled composition, size, geometry, and morphology. In order to enhance biocompatibility, immune compatibility and cell adhesion, surface of these materials can be modified for different application in musculoskeletal tissue scaffolds. Although more tasks and challenges are need to be addressed and resolved in order to translate them into commercialized products, the nanostructured materials represent the very promising candidate in the development of musculoskeletal tissue engineering in the future.
    07/2014; 2(38). DOI:10.1039/C4TB00344F
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study investigates the in vitro cytocompatibility of one- and two-dimensional (1-D and 2-D) carbon and inorganic nanomaterial reinforced polymeric nanocomposites fabricated using biodegradable polymer poly (propylene fumarate), crosslinking agent N-vinyl pyrrolidone (NVP) and following nanomaterials: single- and multi- walled carbon nanotubes, single- and multi- walled graphene oxide nanoribbons, graphene oxide nanoplatelets, molybdenum disulfide nanoplatelets, or tungsten disulfide nanotubes dispersed between 0.02-0.2 wt% concentrations in the polymer. The extraction media of unreacted components, crosslinked nanocomposites and their degradation products between 1X-100X dilutions were examined for effects on viability and attachment employing two cell lines: NIH3T3 fibroblasts and MC3T3 pre-osteoblasts. The extraction media of unreacted PPF/NVP elicited acute dose-dependent cytotoxicity attributed to leaching of unreacted components into cell culture media. However, extraction media of crosslinked nanocomposites showed no dose dependent adverse effects. Further, all crosslinked nanocomposites showed high viability (78-100%), high cellular attachment (40-55%), and spreading that was confirmed by confocal and scanning electron microscopy. Degradation products of nanocomposites showed a mild dose-dependent cytotoxicity possibly due to acidic degradation components of PPF. In general, compared to PPF control, none of the nanocomposites showed significant differences in cellular response to the unreacted components, crosslinked nanocomposites and their degradation products. The initial minor cytotoxic response and lower cell attachment numbers were observed only for a few nanocomposite groups; these effects were absent at later time points for all PPF nanocomposites. The favorable cytocompatibility results for all the nanocomposites opens avenues for in vivo safety and efficacy studies for bone tissue engineering applications.
    Journal of Biomedical Materials Research Part A 11/2014; DOI:10.1002/jbm.a.35363 · 2.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Assembly of carbon nanomaterials into three-dimensional (3D) architectures is necessary to harness their unique physiochemical properties for tissue engineering and regenerative medicine applications. Herein, we report the fabrication and comprehensive cytocompatibility assessment of 3D chemically crosslinked macro-sized (5-8mm height and 4-6mm diameter) porous carbon nanotube (CNT) scaffolds. Scaffolds prepared via radical initiated thermal crosslinking of single- or multi- walled CNTs (SWCNTs and MWCNTs) possess high porosity (>80%), and nano-, micro- and macro-scale interconnected pores. MC3T3 pre-osteoblast cells on MWCNT and SWCNT scaffolds showed good cell viability comparable to poly(lactic-co-glycolic) acid (PLGA) scaffolds after 5 days. Confocal live cell and immunofluorescence imaging showed that MC3T3 cells were metabolically active and could attach, proliferate and infiltrate MWCNT and SWCNT scaffolds. SEM imaging corroborated cell attachment and spreading and suggested that cell morphology is governed by scaffold surface roughness. MC3T3 cells were elongated on scaffolds with high surface roughness (MWCNTs) and rounded on scaffolds with low surface roughness (SWCNTs). The surface roughness of scaffolds may be exploited to control cellular morphology, and in turn govern cell fate. These results indicate that crosslinked MWCNTs and SWCNTs scaffolds are cytocompatible, and open avenues towards development of multifunctional all-carbon scaffolds for tissue engineering applications. This article is protected by copyright. All rights reserved. © 2015 Wiley Periodicals, Inc.
    Journal of Biomedical Materials Research Part A 03/2015; DOI:10.1002/jbm.a.35449 · 2.83 Impact Factor

Full-text

Download
358 Downloads
Available from
Jun 5, 2014