International Journal of NanoScience and Nanotechnology. ISSN 0974-3081 Volume 2, Number 1 (2011), pp. 1-23 © International Research Publication House http://www.irphouse.com Investigations on Zinc Doped Nanocrystalline Hydroxyapatite G. Devanand Venkatasubbu 1* , S. Ramasamy 1 , V. Ramakrishnan 2 , G.S. Avadhani 3 , R. Thangavel 4 and J. Kumar 1 1 Crystal Growth Centre, Anna University, Chennai-600025, Tamil Nadu, India 2 Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai, Tamil Nadu, India 3 Department of Materials Engineering, Indian Institute of Science, Bangalore-560012-India 4 Research Centre for Applied Sciences, Academia Sinica, Taipei 115, Taiwan, Republic of China *Corresponding Author E-mail: gdevanand@gmail.com Abstract Hydroxyapatite is a biocompatible and biodegradable material used in the drug delivery system. Nano hydroxyapatite has been used as an inorganic drug for many years. In this paper, pure nano and zinc added hydroxyapatite were synthesized by wet precipitation method. The presence of single phase was identified by X-ray diffraction. The functional groups present were identified by FTIR spectroscopy. The samples were investigated using micro Raman spectroscopy TEM, EDX, XPS and XRF. TEM observations showed needle shape particles of length up to 100 nm. The addition of zinc in hydroxyapatite is confirmed by FTIR and micro Raman spectroscopy. Pure hydroxyapatite powder and zinc added hydroxyapatite powder were palletized under an uniaxial pressure of 100 MPa and sintered at 900°C for 1 hour. These pellets were used to investigate the antibacterial activity and Vickers micro hardness of pure and zinc doped hydroxyapatite powder nanoparticles. Antibacterial studies showed that pure and zinc doped hydroxyapatite powder have good antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. The antibacterial activity and hardness of zinc added hydroxyapatite was found to increase with increase in the zinc concentration. Keywords: Hydroxyapatite, Drug delivery, Pseudomonas aeruginosa, Staphylococcus aureus, Antibacterial activity, Micro hardness.