www.elsevier.com/locate/jmbbm Available online at www.sciencedirect.com Research Paper A new technique to improve the mechanical and biological performance of ultra high molecular weight polyethylene using a nylon coating Dariush Firouzi a , Aya Youssef b , Momen Amer b , Rami Srouji c , Asma Amleh b,c,nn , Daniel A. Foucher d , Habiba Bougherara a,n a Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Canada M5B 2K3 b Biotechnology Program, American University in Cairo, AUC Avenue, P.O. Box 74, New Cairo 11835, Egypt c Department of Biology, American University in Cairo, Egypt d Department of Chemistry and Biology, Ryerson University, Toronto, Canada article info Article history: Received 16 August 2013 Received in revised form 30 December 2013 Accepted 6 January 2014 Available online 15 January 2014 Keywords: Nylon coating UHMWPE fiber MTT Assay Mechanical properties Osteolysis Cell viability abstract A new patent pending technique is proposed in this study to improve the mechanical and biological performance of ultra high molecular weight polyethylene (UHMWPE), i.e., to uniformly coat nylon onto the UHMWPE fiber (Firouzi et al., 2012). Mechanical tests were performed on neat and new nylon coated UHMWPE fibers to examine the tensile strength and creep resistance of the samples at different temperatures. Cytotoxicity and osteolysis induced by wear debris of the materials were investigated using (MTT) assay, and RT-PCR for tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6) osteolysis markers. Mechan- ical test results showed substantial improvement in maximum creep time, maximum breaking force, and toughness values of Nylon 6,6 and Nylon 6,12 coated UHMWPE fibers between average 15% and 60% at 25, 50, and 70 1C. Furthermore, cytotoxicity studies have demonstrated significant improvement in cell viability using the nylon coated UHMWPE over the neat one (72.4% vs 54.8%) for 48 h and (80.7 vs 5%) for 72 h (Po0.01). Osteolysis test results have shown that the expression levels of TNFα and IL-6 markers induced by the neat UHMWPE fiber were significantly higher than those induced by the Nylon 6,6 coated UHMWPE (2.5 fold increase for TNFα at 48 h, and three fold increase for IL-6 at 72 h (Po0.01)). This study suggests that UHMWPE coated with nylon could be used as a novel material in clinical applications with lower cytotoxicity, less wear debris-induced osteolysis, and superior mechanical properties compared to neat UHMWPE. & 2014 Elsevier Ltd. All rights reserved. 1751-6161/$ - see front matter & 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jmbbm.2014.01.001 Abbreviations: (CNTs), Carbon nanotubes; (DMEM), Dulbecco 0 s Modified Eagle 0 s Medium; (FBS), Fetal Bovine Serum; (HDPE), High density polyethylene; (HA), Hydroxyapatite; (IL-6), Interleukin 6; (MTT), Methylthiazol Tetrazolium; (MWCNTs), Multi wall carbon nanotubes; (PBS), Phosphate buffered saline; (THA), Total hip arthroplasty; (TNFα), Tumor necrosis factor alpha; (UHMWPE), Ultra high molecular weight polyethylene n Corresponding author. Tel.: þ1 416 9795 000x7092; fax: þ1 416 9795265. nn Corresponding author at: Biotechnology Program, American University in Cairo, AUC Avenue, P.O. Box 74, New Cairo 11835, Egypt. Tel.: þ20 22 2615 2908. E-mail addresses: aamleh@aucegypt.edu (A. Amleh), habiba.bougherara@ryerson.ca (H. Bougherara). journal of the mechanical behavior of biomedical materials32 (2014) 198–209