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In vitro deposition of Ca-P nanoparticles on air jet spinning Nylon 6 nanofibers scaffold for bone tissue engineering
(ELSEVIER, 2014-07-15) Abdal-Hay, A; Vanegas Peralta, Pablo Fernando
Microporous, non-woven nylon 6 (N6) scaffolds were prepared with an air jet spinning (AJS) approach. In this process, polymer fibers with diameters down to the nanometer range (nanofibers) were formed by subjecting a fluid jet to high pressure air. The effects of the solution conditions on the morphological appearance and average diameter of the as-spun N6 fibers and crystal structure were investigated. The morphological properties of the AJS membrane mats could easily be tailored by adjusting the concentration of the polymer solution. Solutions at high concentrations were necessary to form well-defined fibers without beads. The production rate (viz. solvent evaporation rate) had the greatest effect on the chain structure conformation of N6. The predominant structure phase of the N6 fibers fabricated by AJS was a thermodynamically stable ?-form while the electrospinning fibers induced the metastable ?-form. AJS significantly enhanced the mechanical properties of the N6 mat. The bone formation ability of AJS fibers was evaluated by incubating the fibers in biomimetic simulated body fluid for 5 and 10 days at 37 °C. Overall, the new AJS approach developed for membrane structures has great potential for the fabrication of hard and soft tissue engineering scaffolds. © 2014 Elsevier B.V. All rights reserved.
Preparation and characterization of vertically arrayed hydroxyapatite nanoplates on electrospun nanofibers for bone tissue engineering
(ELSEVIER, 2014-10-15) Abdal-Hay, A; Vanegas Peralta, Pablo Fernando
The aim of this study is to develop a facile and an efficient approach for providing the electrospun nanofibers scaffold with a vertically well-aligned and homogeneous distribution of hydroxyapatite (HA) nanoplates that coat the scaffold while maintaining its fibrous and porous structure. Crystal growth of HA nanoplates from a colloidal solution onto the surface of nylon (N6) nanofibers was carried out via a hydrothermal approach. The factors affecting the scaffold's morphology, macrostructure and the interfacial bonding between the constituents as well as the influence of crystal size were characterized and well elucidated. The results revealed that the deposition of dense and thick uniform nanoplates was perpendicular and nucleated in a parallel configuration onto the longitudinal axes of the individual nanofibers during the treatment process. The sizes of the nanoplates, which are strongly dependent on the reaction time, were 30 and 95. nm in length, with thicknesses of 17-19. nm, after 2 and 3. h respectively. The nanoplates improve the mechanical properties of the HA/N6 biocomposite scaffolds. The surface properties of the fabricated scaffolds appeared to have a greater effect on the early stages of osteoblast behavior (cell attachment and proliferation). The cells attached, grew and proliferated faster on culture-coated scaffolds in comparison with the pristine ones. Our results indicate that the treated scaffolds fulfill the basic requirements of bone tissue engineering scaffolds, and have the potential to be applied in orthopedic and reconstructive surgeries. © 2014 Elsevier B.V.
TiO2 nanorods coated onto nylon 6 nanofibers using hydrothermal treatment with improved mechanical properties
(ELSEVIER B.V., 2014-09-05) Abdal-Hay, A; Vanegas Peralta, Pablo Fernando
Well-aligned arrays TiO2 nanorods were deposited onto electrospun nylon 6 (N6) nanofibers. The complete coverage of individual fiber surfaces with TiO2 nanorods occurred in a very short time using a cost effective hydrothermal technique. The results demonstrate that organic molecule substrates have a considerable influence on nucleation and precipitation mechanism and uniform distribution behaviors of TiO2 onto N6 nanofibers surface with good interfacial adhesion between the components. N6 decorated with large number TiO2 nanorods showed good hydrophilicity. Significant improvement in mechanical properties like tensile strength and modulus of the TiO2/N6 composite membrane mats in comparison to the pristine N6 mats was observed by applying just 2h reaction process. The resultant TiO2/N6 spider-net like composite mat with good hydrophilicity may be a potential candidate for future water filter applications, and its improved mechanical will also make it a potential candidate for protective clothing. © 2014 .

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