Journal of Biotechnology 131S (2007) S65–S68 Health and Medicine NANOTECHNOLOGY IN MEDICINE 1. Application of magnetic bio-nanoparticles to the control of stem cell behavior Tai Hyun Park ∗ , Hong Jai Lee, Jeong Ah Kim, Seung Hwan Lee Seoul National University, Gwanak-Gu Sillim-Dong San 56-1, 151-744 Seoul, South Korea Cell therapy using stem cells is a promising method to treat inveterate diseases like myocardial infarction and spinal cord injury. But there are some obstacles in the stem cell therapy, which include the problems in homing and fixing myocar- dial stem cells to desired site and guiding neurite extension of neural stem cell to specific direction. In this study, mag- netic nanoparticles were used to overcome these challenges in therapeutic application of stem cells. A magnetic bacteria strain, Magnetospirillium magneticum AMB-1, contains mag- netic nanoparticles in it, which have 40–50 nm diameter and lipid bilayer on their surface (Matsunaga, 1991). The magnetic bacterial strain and magnetic nanoparticles have been used for various researches (Seong and Park, 2001; Kim et al., 2005). The magnetic bio-nanoparticles were harvested from the bacte- ria and introduced into stem cells. It was observed that magnetic nanoparticle introduced cells moved to a specific direction on external magnetic field and fixed at the desired site. References Kim, H.K., Hong, S.H., Hwang, S.W., Hwang, J.S., Ahn, D., Seong, S., Park, T.H., 2005. J. Appl. Phys. 98, 104307. Matsunaga, T., 1991. Trends Biotechnol. 9, 91–95. Seong, S., Park, T.H., 2001. Biotechnol. Bioeng. 76, 11–16. doi:10.1016/j.jbiotec.2007.07.112 2. Production and characterization of bioceramic nano- powders of natural-biological origin Umut T¨ uyel a,∗ , Ebru Toksoy ¨ Oner a , Sevgi ¨ Ozyegin b , Faik N. Oktar c a Marmara University, Faculty of Engineering, Chemical Engi- neering Department, G ¨ oztepe Campus, 34722 Istanbul, Turkey b Dental Technology Department, School of Health Related Pro- fessions, Marmara University, G¨ oztepe, 34722 Istanbul, Turkey c Department of Industrial Engineering, Marmara University, G¨ oztepe, 34722 Istanbul, Turkey Living in the era of life control and prolongation, calcium phosphate-based biomaterials such as hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP) are considered as promis- ing bioceramics for both delivering drugs and increasing bone mass. HA are very popular for hard tissue (e.g., bone) restora- tions because they accelerate bone growth around the implant (Rocha et al., 2005). Having a calcium–phosphorus ratio simi- lar to natural bone mineral, low-density, highly porous beta-TCP have been proposed as potential bone defect fillers where they fill the void and gradually dissolve away due to their resorbable nature, being replaced by bone. For preparing nano-powders of calcium phosphates, nacres are considered as suitable natural materials for dental and bone restorations. Besides their world- wide availability and low cost, they are able to initiate and induce mineralized tissue formation by human osteoblasts in vitro and also exhibit osteogenic and osteoinductive features by devel- oping bonds with bones (Lemos et al., 2006). The present work aims at preparing inexpensive nano-sized HA and beta-TCP par- ticles from various raw materials of natural-biological origin. These materials include the bones of cuttlefish Sepia officianalis, Chinese sweet water Pearl Powder, the Pacific Kumamoto oys- ter Crassostrea sikamea, the bivalve mollusc Venus verrucosa collected from Turkish and Portuguese beaches and the com- mon European oyster Ostrea edulis. Each sample was reduced to sub100 m particle size and Differential thermal analy- sis (DTA/TG) was employed to determine their exact CaCO 3 content. The morphology of HA and beta-TCP powders was 0168-1656/$ – see front matter doi:10.1016/j.jbiotec.2007.07.111