Cytotoxic Properties of Calcium Phosphate/Multi-Walled Carbon Nanotubes/Bovine Serum Albumin on the CCD-18Co Cell Line

Every year, more than 2.2 million bone grafting procedures are performed worldwide. Bone tissue engineering seeks to develop strategies to heal bone loss due to disease without the drawbacks and impediments of existing clinical autografting and allografting treatments [1]. One of the most promising groups of synthetic bone replacements is calcium phosphate cements (CPCs). Due to the similarity between CPCs and the mineral phase of bone, as well as the in situ setting ability of CPCs, CPCs are potential materials for use in minimally invasive surgery and are considered a promising material to repair bone defects [2]. CPCs have been developed as injectable bone substitutes (IBS) due to their biocompatibility, excellent bioactivity, self-setting characteristics, low setting temperature, adequate stiffness and easy shaping into complicated geometries[3,4]. A number of CPC products are available commercially; however, they have limited compressive strength, so the use of CPCs is restricted primarily to non-stress-bearing applications, such as in maxillofacial surgery, the repair of cranial defects and dental fillings [5-7]. To overcome these problems and challenges, the combination of CPCs with carbon nanotubes (CNTs) is being increasingly investigated to exploit the extraordinary mechanical properties of CNTs to reinforce bioceramic matrices [8,9]. CNTs have an excellent potential to reinforce CPCs based on their small dimensions, high aspect ratio (length to diameter) and high strength and stiffness [10]. Incorporation of CPC with proteins, such as bovine serum albumin (BSA), was suggested to prepare improved calcium phosphate ceramics [11-15]. The addition of low concentrations of BSA has been shown to enhance calcium phosphate crystal growth, whereas higher concentrations inhibited calcium phosphate crystallization [13,15].