%0 Journal Article
%T Effect of Synthesis Temperature on the Crystallization and Growth of In Situ Prepared Nanohydroxyapatite in Chitosan Matrix
%A Habiba Elhendawi
%A R. M. Felfel
%A Bothaina M. Abd El-Hady
%A Fikry M. Reicha
%J ISRN Biomaterials
%D 2014
%R 10.1155/2014/897468
%X Hydroxyapatite nanoparticles (nHA) have been used in different biomedical applications where certain particle size distribution and morphology are required. Chitosan/hydroxyapatite (CS/HA) nanocomposites were prepared using in situ coprecipitation technique and the effect of the reaction temperature on the crystallization and particle growth of the prepared nanohydroxyapatite particles was investigated. The composites were prepared at different synthesis temperatures (£¿10, 37, and 60¡ãC). XRD, FTIR, thermal analysis, TEM and SEM techniques were used to characterize the prepared specimens. It was found that the increase in processing temperature had a great affect on particle size and crystal structure of nHA. The low temperature (£¿10¡ãC) showed inhabitation of the HA growth in c-direction and low crystallinity which was confirmed using XRD and electron diffraction pattern of TEM. Molar ratio of the bone-like apatite layer (Ca/P) for the nanocomposite prepared at 60¡ãC was higher was higher than the composites prepared at lower temperatures (37 and £¿10¡ãC). 1. Introduction Natural bone is a complex inorganic-organic nanocomposite, in which hydroxyapatite [HA, Ca10(PO4)6(OH)2] nanocrystallites and collagen fibres are well arranged in a hierarchical architecture [1]. High mechanical strength and fracture toughness of the bone were attributed to reinforcement of flexible collagen fibers with HA nanocrystals [2]. Bone is one of the human body tissues that can be replaced or repaired after fracture [3]. Bone can be repaired by autografts, allografts, or use of implant (e.g., scaffold, screws, nail, and plates). Bone fixation devices have been widely used in order to obviate the complications of autografts and allografts procedures such as infection and pain [4, 5]. Metallic implants have been applied for bone fixation since 1895 [6]. However, bioresorbable polymers such as poly lactic acid, poly glycolic acid, and chitosan were introduced as alternative for metals to overcome the complications of metallic devices such as stress shielding, corrosion, and removal surgery [7]. Bioresorbable polymers have been applied for biomedical application due to their various properties (e.g., biocompatibility, biodegradability, porosity, charge, mechanical strength, and hydrophobicity). Furthermore, they could be chemically modified by change of polymerization conditions and ratios of the monomers within the copolymers [1]. Natural polymers such as chitosan (CS) have been replacing synthetic polymers due to their biocompatibility and nontoxic nature of their degradation
%U http://www.hindawi.com/journals/isrn.biomaterials/2014/897468/