Delivered by Ingenta to: University of South Carolina IP: 193.0.129.127 On: Mon, 13 Jun 2016 07:54:44 Copyright: American Scientific Publishers RESEARCH ARTICLE Copyright © 2010 American Scientific Publishers All rights reserved Printed in the United States of America Journal of Biomedical Nanotechnology Vol. 6, 333–339, 2010 Synthesis and Characterization of Nanoscale- Hydroxyapatite-Copper for Antimicrobial Activity Towards Bone Tissue Engineering Applications K. Sahithi 1 , M. Swetha 1 , M. Prabaharan 2 , A. Moorthi 1 , N. Saranya 1 , K. Ramasamy 1 , N. Srinivasan 3 , N. C. Partridge 4 , and N. Selvamurugan 1 3 4 ∗ 1 Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur 603203, Tamil Nadu, India 2 Department of Chemistry, Faculty of Engineering and Technology, SRM University, Kattankulathur 603203, Tamil Nadu, India 3 Department of Endocrinology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras Taramani, Chennai 600113, Tamil Nadu, India 4 Department of Basic Biology and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA The bacterial infection is one of the major problems associated with implant and reconstructive surgery of bone. Hence, the aim of this study was to develop biomaterials having antibacterial activ- ity for bone tissue engineering. The hydroxyapatite nanoparticles (nHAp) improve the mechanical properties and incorporate nanotopographic features that mimic the nanostructure of natural bone. We report here for the first time the synthesis and characterization of nHAp and nHAp soaked with copper (nHAp-Cu) using SEM, AFM, FTIR and XRD. The antibacterial activity of nHAp and nHAp-Cu was determined using Gram-positive and Gram-negative bacterial strains. To have accel- erated antibacterial activity, polyethylene glycol 400 (PEG 400), a synthetic biodegradable polymer was also added along with nHAp-Cu. The nHAp-Cu/PEG 400 had increased antibacterial activity towards Gram-positive than Gram-negative bacterial strains. The cytotoxicity of nHAp-Cu/PEG 400 was determined using MTT assay with rat primary osteoprogenitor cells and these biomaterials were found to be non-toxic. Hence, based on these results we suggest that the biomaterials containing nHAp-Cu/PEG 400 can be used as antibacterial materials in bone implant and bone regenerative medicine. Keywords: Nano-Hydroxyapatite Particles, Nano-Hydroxyapatite Soaked with Copper, Polyethylene Glycol, Antibacterial Activity. 1. INTRODUCTION Natural bone contains three levels of hierarchical structures namely nano, micro and macro structure. The nanostructure (a few nanometers to a few hundred nanometers) acts as a cell and mineral binding architecture which includes non-collageneous organic proteins, fibrillar collagen and embedded mineral (HA) crystals. The microstructure (from 1 to 500 mm) includes lamellae, osteons, and Haversian systems for cell migration and vascularization; and the macrostructure includes cancellous and cortical bone for mechanical anisotropy. Bone has the unique capacity to promote angiogenesis and osteogenesis for self-healing. 1 2 Bone regeneration research has been emerged for treat- ing various bone diseases such as bone infections, bone ∗ Author to whom correspondence should be addressed. tumours and bone loss by trauma. 3 Since autografts and allografts used in bone regeneration have few limitations including the risk of infection, bone tissue engineering substitutes are another choice for treating bone defects to regenerate bone. 4 The development of materials by mim- icking the structure and composition of human tissue, namely the biomimtic approach, has long been a major goal in the field of bone tissue engineering. 5 Many biomaterials as implants are widely used to replace and/or restore the function of traumatized or degenerated tissues or organs, to assist in healing, to improve function. 9 Ceramic mate- rials like calcium phosphates are suitable as bone substi- tutes due to their biocompatible, bioactive, biodegradable, and osteoconductive characteristics, and when implanted in vivo, they are nontoxic and do not induce any anti- genic response. 6 7 A number of synthetic biodegradable polymers like poly(caprolactone), poly(lactic-co-glycolic J. Biomed. Nanotechnol. 2010, Vol. 6, No. 4 1550-7033/2010/6/333/007 doi:10.1166/jbn.2010.1138 333