Hindawi Publishing Corporation Te Scientifc World Journal Volume 2013, Article ID 162384, 6 pages http://dx.doi.org/10.1155/2013/162384 Research Article The Influence of -Ray Irradiation on the Mechanical and Thermal Behaviors of nHA/PA66 Composite Scaffolds Fu You, Yubao Li, Yi Zuo, and Jidong Li Research Center for Nano-Biomaterials, Analytical & Testing Center, Sichuan University, Chengdu 610064, China Correspondence should be addressed to Jidong Li; nic1979@scu.edu.cn Received 29 August 2013; Accepted 8 October 2013 Academic Editors: R. Adhikari and K. Ishikawa Copyright © 2013 Fu You et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te aim of this study is to investigate the infuence of sterilization process using -ray radiation on the melting behavior, crystallization behavior, thermal stability, and mechanical properties of nanohydroxyapatite/polyamide66 (nHA/PA66) scafolds for bone tissue engineering. Te results show that the melting temperature, degree of crystallization, thermal stability, and mechanical properties of the composite scafolds increased with the enhancement of radiation doses from 25 kGy to 50 kGy, especially the irradiation dose of 50 kGy which imposed a remarkable efect on these properties. However, a reverse trend was found when the 100 kGy irradiation dose was applied. In general, a conclusion can be drawn that sterilization using -ray radiation with proper dose has no adverse efect on the properties of nHA/PA66 composite scafolds. 1. Introduction Porous scafolds have been proved to play an important role in bone tissue engineering. Te composite scafolds have recently become a research hotspot due to its combination of the advantages of the diferent components in the composite. Based on the biomimic mechanism of the unique structure of hydroxyapatie/collagen in natural bone, a composite system consisting of nanohydroxyapatite (nHA) and polyamide 66 (PA66) was designed by our group [1] and had achieved favorable clinical efect [2]. Nanohydroxyapatite (HA) owns a considerable similarity in composition and structure to that of natural bone minerals, which consequently renders them osteoconductive and even osteoinductive, while the polymer phase of PA66 endows excellent mechanical properties to the nHA/PA66 composites. Te nHA/PA66 composite scafolds have been successfully developed by our group, which have exhibited desirable biocompatibility and osteogenesis [3]. It is well known that once the biomaterials have been manufactured, the devices must be sterilized prior to implan- tation. Te sterilization methods used for biomedical devices include moist heat sterilization, radiation sterilization, and ethylene oxide sterilization. Moist heat sterilization is not suitable for the temperature-sensitive materials or for the products which need long-term storage. Ethylene oxide sterilization is one of the most commonly used methods which is known to cause little or no changes to the mechanical properties of the material [4]; however the potential toxicity resulting from ingredients residual limits its widespread application. Gamma radiation sterilization method, however, using typically a minimum of 25 kGy irradiation dose from a 60 Co source, is widely used in the medical industry due to its efciency and reliability, which can be carried out in air or in an inert environment. Te efect of ionization radiation on polymers is known to be one of the major sources for altering their internal structure, thus leading to a wide range of interrelated changes in their physicochemical properties. Such treatment may result in cross-linking and scission of the molecular chains of polymers or even degradation and destruction of the macromolecules, that is, formation of molecules with smaller chain lengths or change in the number or nature of the double bonds within the polymer backbone [5, 6]. While scission and crosslinking always occur to some degree in the materials subjected to gamma radiation, the presence of oxygen during radiation sterilization favored chain scission mechanisms and oxidative degradation. Termal analysis is a vital analytical method in understanding the structure-property relation- ships and mastering the technology for molecular design and industrial production of diferent polymeric materials,