Mechanical and thermal properties of polypeptide modified hydroxyapatite/poly(L-lactide) nanocomposites

Wei, Junchao; Dai, Yanfeng; Chen, Yiwang; Chen, Xuesi

doi:10.1007/s11426-011-4221-2

Cited by 13 publications

(6 citation statements)

References 25 publications

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“…There were weak shoulder peaks in the curves ( Figure 7 , curve (c)); in other words, two melting peaks were found. This finding of two melting points for PLLA samples has also been observed in many other references [ 25 , 26 ], and this phenomenon can be ascribed to the differences of crystal morphology. As a matter of fact, when PLLA samples crystallize at a faster speed, there will be more uncompleted crystalline phase, which will melt at a lower temperature.…”

Section: Resultssupporting

confidence: 88%

Graphene Oxide-Graft-Poly(l-lactide)/Poly(l-lactide) Nanocomposites: Mechanical and Thermal Properties

Wang

Wei

2017

Polymers

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Abstract:The surface modification of graphene sheets with polymer chains may greatly hinder its aggregation and improve its phase compatibility with a polymer matrix. In this work, poly(L-lactic acid)-grafted graphene oxide (GO-g-PLLA) was prepared via a simple condensation polymerization method, realizing its dispersion well in organic solvents, which demonstrated that the surface of GO changed from hydrophilic to hydrophobic. GO-g-PLLA can disperse homogeneously in the PLLA matrix, and the tensile test showed that the mechanical properties of GO-g-PLLA/PLLA were much better than that of GO/PLLA; compared with GO, only 3% GO-g-PLLA content can realize a 37.8% increase in the tensile strength for their PLLA composites. Furthermore, the differential scanning calorimetry (DSC) and polarized optical microscopy (POM) results demonstrated that GO-g-PLLA shows a nucleating agent effect and can promote the crystallization of PLLA.

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Section: Resultssupporting

confidence: 88%

Graphene Oxide-Graft-Poly(l-lactide)/Poly(l-lactide) Nanocomposites: Mechanical and Thermal Properties

Wang

Wei

2017

Polymers

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“…Composites and nanocomposites based on bioresorbable thermoplastic aliphatic polyesters, i.e., poly(L-lactide) (PLLA), polycaprolactone (PCL) or copolymers thereof (like PGLA) and calcium hydroxyapatites have been widely studied due to their potential applications in regenerative medicine, especially for bone tissue engineering [12,20,21,22,23,24,25,26,27]. Usually, these systems can be used as implants for small bone defects or as scaffolds [28,29].…”

Section: Introductionmentioning

confidence: 99%

The Comprehensive Approach to Preparation and Investigation of the Eu3+ Doped Hydroxyapatite/poly(L-lactide) Nanocomposites: Promising Materials for Theranostics Application

et al. 2019

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In response to the need for new materials for theranostics application, the structural and spectroscopic properties of composites designed for medical applications, received in the melt mixing process, were evaluated. A composite based on medical grade poly(L-lactide) (PLLA) and calcium hydroxyapatite (HAp) doped with Eu3+ ions was obtained by using a twin screw extruder. Pure calcium Hap, as well as the one doped with Eu3+ ions, was prepared using the precipitation method and then used as a filler. XRPD (X-ray Powder Diffraction) and IR (Infrared) spectroscopy were applied to investigate the structural properties of the obtained materials. DSC (Differential Scanning Calorimetry) was used to assess the Eu3+ ion content on phase transitions in PLLA. The tensile properties were also investigated. The excitation, emission spectra as well as decay time were measured to determine the spectroscopic properties. The simplified Judd–Ofelt (J-O) theory was applied and a detailed analysis in connection with the observed structural and spectroscopic measurements was made and described.

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“…For these reasons biopolymers like PLLA, which are fabricated from renewable agriculture materials and then biodegraded back to water and carbon dioxide, have been used widely as tissue engineering scaffolds [24] . In the present study, we combined both HA and PLLA to overcome the shortcomings of each material and unite their advantages to achieve better mechanical and biomaterial properties [8] . At present, the use of HA/PLLA scaffolds [25] has demonstrated good material degradation profiles in tissues, biocompatibility as well as mechanical and crystallization properties [26] , [27] .…”

Section: Discussionmentioning

confidence: 99%

“…PBLG-g-HA was synthesized according to our previous work [28] where the structure, crystalline, dispersion test and biocompatibility were ideal for a bone grafting material. The polymer brushes (PBLG) are used to improve the phase compatibility between HA and PLLA, and thus have positive effect on its mechanical properties [29] . Furthermore, the PBLG brushes may also affect thermal properties of the composites [30] .…”

Section: Discussionmentioning

confidence: 99%

“…Previously, Chen’s group have prepared polypeptide poly (γ-benzyl-L-glutamate) modified HA nanoparticles (PBLG-g-HA) by the ring opening polymerization of γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA), and their research has demonstrated that PBLG-g-HA can maintain higher colloidal stability and improve cell adhesion when compared to that of pure HA. In addition, the mechanical properties of PBLG-g-HA/PLLA composites were higher than that of HA/PLLA [8] , [16] . The aim of the present study was to extrapolate the findings from recent studies eliciting the advantages of PLLA incorporating with PBLG-g-HA nanoparticles and create a homogeneous scaffold of PBLG-g-HA/PLLA.…”

Section: Introductionmentioning

confidence: 90%

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Osteogenic Properties of PBLG-g-HA/PLLA Nanocomposites

et al. 2014

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New development of biomaterial scaffolds remains a prominent issue for the regeneration of lost or fractured bone. Of these scaffolds, a number of bioactive polymers have been synthesized and fabricated for diverse biological roles. Although recent evidence has demonstrated that composite scaffolds such as HA/PLLA have improved properties when compared to either HA or PLLA alone, recent investigations have demonstrated that the phase compatibility between HA and PLLA layers is weak preventing optimal enhancement of the mechanical properties and making the composites prone to breakdown. In the present study, poly (γ-benzyl-L-glutamate) modified hydroxyapatite/(poly (L-lactic acid)) (PBLG-g-HA/PLLA) composite scaffolds were fabricated with improved phase compatibility and tested for their osteogenic properties in 18 Wistar female rats by analyzing new bone formation in 3 mm bilateral femur defects in vivo. At time points, 2, 4 and 8 weeks post surgery, bone formation was evaluated by µ-CT and histological analysis by comparing 4 treatment groups; 1) blank defect, 2) PLLA, 3) HA/PLLA and 4) PBLG-g-HA/PLLA scaffolds. The in vivo analysis demonstrated that new bone formation was much more prominent in HA/PLLA and PBLG-g-HA/PLLA groups as depicted by µ-CT, H&E staining and immunohistochemistry for collagen I. TRAP staining was also utilized to determine the influence of osteoclast cell number and staining intensity to the various scaffolds. No significant differences in either staining intensity or osteoclast numbers between all treatment modalities was observed, however blank defects did contain a higher number of osteoclast-like cells. The results from the present study illustrate the potential of PBLG-g-HA/PLLA scaffolds for bone tissue engineering applications by demonstrating favorable osteogenic properties.

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Mechanical and thermal properties of polypeptide modified hydroxyapatite/poly(L-lactide) nanocomposites

Cited by 13 publications

References 25 publications

Graphene Oxide-Graft-Poly(l-lactide)/Poly(l-lactide) Nanocomposites: Mechanical and Thermal Properties

Graphene Oxide-Graft-Poly(l-lactide)/Poly(l-lactide) Nanocomposites: Mechanical and Thermal Properties

The Comprehensive Approach to Preparation and Investigation of the Eu3+ Doped Hydroxyapatite/poly(L-lactide) Nanocomposites: Promising Materials for Theranostics Application

Osteogenic Properties of PBLG-g-HA/PLLA Nanocomposites

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