Stereocomplexation Reinforced High Strength Poly(L-lactide)/Nanohydroxyapatite Composites for Potential Bone Repair Applications

Abstract

Composite materials composed of polylactide (PLA) and nano-hydroxyapatite (n-HA) have been recognized as excellent candidate material in bone repai The difference in hydrophilicity/hydrophobicity and poor interfacial compatibility between n-HA filler and PLA matrix leads to non-uniform dispersion of n-HA in PLA matrix and consequent poor reinforcement effect. In this study, an HA/PLA nanocomposite was designed based on the surface modification of n-HA with poly(D-lactide) (PDLA), which not only can improve the dispersion of n-HA in the poly(L-lactide) (PLLA) matrix but also could form a stereocomplex crystal with the matrix PLLA at the interface and ultimately lead to greatly enhanced mechanical performance The n-HA/PLA composites were characterized by means of scanning electron microscopy, Fourier transform infrared spectroscopy, X-Ray diffraction, thermal gravity analysis, differential scanning calorimetry, and a mechanical test; in vitro cytotoxicity of the composite material as well as its efficacy in inducing osteogenic differentiation of rat bone marrow stromal cells (rMSCs) were also evaluated. Compared with those of neat PLLA, the tensile strength, Young’s modulus, interfacial shear strength, elongation at break and crystallinity of the composites increased by 34%, 53%, 26%, 70%, and 17%, respectively. The adhesion and proliferation as well as the osteogenic differentiation of rMSCs on HA/PLA composites were clearly evidenced. Therefore, the HA/PLA composites have great potential for bone repai

Understanding the Impact of Chain Mobility on Conformational Evolution and Kinetics of Mesophase Formation in Poly(ʟ-lactide) under Low-Pressure CO2

“…Because of its high biocompatibility, good processability, and considerable mechanical properties, poly(Ï-lactide) (PLLA) exhibits wide applications in various fields such as packaging materials, medical devices, and textiles [1][2][3][4][5][6][7][8]. As a semicrystalline polymer, the physical properties of PLLA can be regulated by controlling its crystalline structure and morphology [8][9][10][11][12][13]. Specifically, by controlling the processing or crystallization conditions, the crystal orientation, crystallinity, and chain packing modes of PLLA can be tailored.…”

Preparation and Characterization of a Novel Tragacanth Gum/Chitosan/Sr-Nano-Hydroxyapatite Composite Membrane

“…However, pure CS membrane lacks osteoconductivity for guided bone tissue regeneration. To improve the osteogenic effectiveness, nano-hydroxyapatite (n-HA) is usually chosen to obtain the n-HA/CS composite membrane because n-HA has osteoconductivity and osteinductivity due to its similar chemical composition with the natural bone [8][9][10]. Unfortunately, the poor mechanical properties of the n-HA/CS composite were expected to increase, and the fast degradation needs to be slowed down.…”