Poly(propylene fumarate)/Polyethylene Glycol-Modified Graphene Oxide Nanocomposites for Tissue Engineering

Abstract

Poly(propylene fumarate) (PPF)-based nanocomposites incorporating different amounts of polyethylene glycol-functionalized graphene oxide (PEG-GO) have been prepared via sonication and thermal curing, and their surface morphology, structure, thermal stability, hydrophilicity, water absorption, biodegradation, cytotoxicity, mechanical, viscoelastic and antibacterial properties have been investigated. SEM and TEM images corroborated that the noncovalent functionalization with PEG caused the exfoliation of GO into thinner flakes. IR spectra suggested the presence of strong hydrogen-bonding interactions between the nanocomposite components. A gradual rise in the level of hydrophilicity, water uptake, biodegradation rate, surface roughness, protein absorption capability and thermal stability was found upon increasing GO concentration in the composites. Tensile tests revealed improved stiffness, strength and toughness for the composites compared to unfilled PPF, ascribed to a homogeneous GO dispersion within the matrix along with a strong PPF/PEG-GO interfacial adhesion via polar and hydrogen bonding interactions. Further, the nanocomposites retained enough stiffness and strength under a biological state to provide effective support for bone tissue formation. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus and Staphylococcus epidermidis as well as Gram-negative Pseudomonas aeruginosa and Escherichia coli microorganisms, and it rose sharply upon increasing GO concentration; systematically, the biocide effect was stronger versus Gram-positive bacteria. Cell viability data demonstrated that PPF/PEG-GO composites do not induce toxicity over human dermal fibroblasts. These novel materials show great potential to be applied in the bone tissue engineering field.

Bone Tissue Engineering via Carbon‐Based Nanomaterials

“…Thus, GO, which has excellent mechanical properties, has been studied as a filler material together with various polymers to improve their mechanical performances. As expected, a small amount of GO (i.e., 1% in weight percentage) would significantly improve the mechanical properties of the composite scaffolds . However, it is worth noting that in some cases too much of GO in the composites might be detrimental to the mechanical performance .…”

“…Thanks to the rich presence of polar oxygen‐containing functionalities, the addition of GO can also increase the hydrophilicity of the composite materials. Many groups have reported the decrease in the water contact angles upon the addition of GO to their polymeric scaffold materials . The enhancement of hydrophilicity significantly improved the protein and cell adhesion strength of the composite materials, which is a key parameter for BTE scaffold fabrications.…”

“…As expected, a small amount of GO (i.e., 1% in weight percentage) would significantly improve the mechanical properties of the composite scaffolds. [93][94][95][96][97][98] However, it is worth noting that in some cases too much of GO in the composites might be detrimental to the mechanical performance. [93,96,97] For example, in Chatterjee's study, the Young's modulus of galactitol polyester increases as the addition of GO increased from 0.5 to 1 wt.% while a dramatic decrease in modulus was observed as the addition of GO increased to 2 wt.%.…”

“…Many groups have reported the decrease in the water contact angles upon the addition of GO to their polymeric scaffold materials. [93][94][95]99] The enhancement of hydrophilicity significantly improved the protein and cell adhesion strength of the composite materials, which is a key parameter for BTE scaffold fabrications. With the improved cell adhesion, the cell viability and proliferation have also been increased.…”

Thermally conductive thin films derived from defect free graphene-natural rubber latex nanocomposite: Preparation and properties

“…These diversities in graphene enable efficient modulation of interfacial adhesion and enhance its compatibility with number of polymers [12], [13], [14], [15], [16], [17], [18], [19] such as polyaniline, polylactic acid, polycaprolactone, PEG etc. In general, graphene production methods can be categorized as two a) bottom-up methods (e.g.…”