Development Of Multiwalled Carbon Nanotubes Reinforced Hydroxyapatite
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Date
2014-09
Authors
Gholami, Fatemeh
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Abstract
The similarity of the chemical composition of hydroxyapatite (HA) to the mineral phase of bone and their excellent biocompatibility meets the requirement of materials designed for bone repair and augmentation purposes. However, the application of HA in load bearing devices is limited by its poor mechanical properties. Carbon nanotubes (CNTs), with their outstanding stiffness and strength, have good potential applications in tissue engineering. Their strength and stiffness, combined with their small size and large interfacial surface area, suggest that they may have great potential as a reinforcing agent for HA. In this study, Hydroxyapatite/Multiwalled carbon nanotubes/Bovine serum albomin (HA/MWCNTs/BSA) composites with highly improved mechanical properties for use as bone replacement materials were developed. The HA/MWCNTs/BSA composites powders with different types of MWCNTs (MWCNTs-OH, MWCNTs-COOH, MWCNTs) were successfully prepared. The results show that the HA composites which are prepared by using MWCNTs-COOH and BSA with compressive strength of 29.75 MPa has the highest results in comparison with HA composites which are prepared by using other types of MWCNTs. The HA/MWCNTs-COOH/BSA composite immersed in SBF for 7, 14, 21 and 28 days in 37 °C as in vitro biological test in with the purpose to investigate the SBF effects on mechanical properties. The compressive strength of immersed composites in SBF was decreased from 29.57 to 9.11 MPa after 28 days immersing. The nano-HA with particle size in the range 20 to 25 nm was successfully synthesized using precipitation technique from Ca(NO3)2.4H2O and (NH4)2HPO4 solution. The Nano-
HA/MWCNTs-COOH/BSA composites were successfully produced using precipitation technique. The synthesized composites calcined at different temperatures of 600, 800 and 1000 °C. The compressive strength of Nano-HA/MWCNTs-COOH/BSA composites after calcination at 600, 800 and 1000 °C are 27.01, 27.78 and 37.43 MPa respectively. The cytotoxic effect of the test samples with different concentrations was evaluated by MTT assay against normal human colon fibroblast. At low concentration, all developed composites were found to be non-cytotoxic when treated to the human fibroblast cells and did not elicit cytotoxic effects on cell proliferation, whereas when the concentration of samples was increased, the reduction in cell viability was observed. The HA/MWCNTs-OH/BSA, HA/MWCNTs-COOH/BSA, and HA/MWCNTs/BSA composites showed the proliferative effects on the cells. The samples used in the present study did not show toxic effects as proliferation was induced. Furthermore, the Nano-HA/MWCNTs-COOH/BSA implies a cell proliferative effect on CCD-18Co cell line. HA/MWCNTs-OH/BSA, HA/MWCNTs-COOH/BSA, HA/MWCNTs/BSA and Nano-HA/MWCNTs-COOH/BSA composites are possibly a good choice to develop orthopedic materials because these materials passed the entire filter, in which a desirable effect was elicited in the body. Furthermore, these compounds can enter the market industry with a possibly high success rate.
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Keywords
The chemical composition of hydroxyapatite , materials designed for bone repair