Crystallinity and Reinforcement in Poly-L-Lactic Acid Scaffold Induced by Carbon Nanotubes

Abstract

Poly-L-Lactic Acid (PLLA) is a bioabsorbable implant material due to its favorable biocompatibility and inherent degradability, while the insufficient mechanical strength hinders its further bone repair application. In present work, carbon nanotubes (CNTs) were introduced into PLLA scaffolds fabricated via selective laser sintering. It was found that the crystallinity of PLLA increased considerably since CNTs could promote the orderly stacking of its molecular chains, thereby improving the mechanical strength of PLLA scaffold. Furthermore, the fracture surface analysis revealed that CNTs acted as a bridge across the cracks and hindered their further expansion. Moreover, CNTs pulled out from the matrix to consume a large amount of fracture energy, which enhanced the resistance to external forces. As a consequence, the compressive strength, Vickers hardness and tensile strength of the scaffold were enhanced by 22.7%, 58.8% and 17.6%, respectively. Besides, the cells exhibited good attachment, spreading and proliferation on the scaffold. This study demonstrated that PLLA/CNTs scaffold was a promising candidate as bone implant.

Graphene Oxide Induces Ester Bonds Hydrolysis of Poly-l-lactic Acid Scaffold to Accelerate Degradation

“…Graphene oxide (GO) is a two-dimensional lamellar structure with a large amount of oxygen-containing functional groups (such as –COOH and –OH) on its surface[ 19 - 22 ]. These functional groups can endow GO good hydrophilic property and water absorption capacity[ 23 - 26 ].…”

Surface-Modified Graphene Oxide with Compatible Interface Enhances Poly-L-Lactic Acid Bone Scaffold

“…Incorporating reinforcement phases to obtain a composite material is a feasible method to overcome this issue [6][7][8]. Nanofillers such as graphene oxide [9,10], carbon nanotubes [11,12], diamond nanoparticles [13,14], and magnesium oxide nanoparticles [15][16][17] have been introduced into PLLA matrix to improve the mechanical performance. Amongst them, GO as a reinforcement phase was used to enhance the polymer due to its unique mechanical strength, including a strength of approximately 130 GPa and modulus of approximately 1 TPa [18].…”

In situ decomposition of Ti2AlN promoted interfacial bonding in ZnAl-Ti2AlN biocomposites for bone repair

“…Zn alloys are introduced as a new class of bio absorbable metals for biomedical application owing to their good biocompatibility as well as nearly ideal biodegradation rate [1][2][3][4][5]. In terms of biocompatibility, as an abundant element in the human body, Zn plays a vital role in cell proliferation and the metabolism of human body [6][7][8][9].…”