1 ANALYSIS OF BONE COMPOSITION WITH RAMAN SPECTROSCOPY Kalonakis Konstantinos, Orkoula Malvina and Kontoyannis Christos * Department of Pharmacy, University of Patras, 26500 Patras, Greece and Institute of Chemical Engineering and High Temperature Chemical Processes, FORTH, Patras, Greece ABSTRACT Bone is a composite material formed by the nucleation and growth of a mineral highly resembling calcium hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 , within an organic matrix consisting mainly of type I collagen. Seventy percent of mature bone consists of the inorganic phase while the organic matrix and water fills the rest. Development of fast and reliable methodologies capable of analyzing chemically the major bone constituents is needed. In the present work, Raman spectroscopy, a non-destructive technique, was applied as such a tool on bovine cortical and trabecular parts of bone. Preliminary results show that their mineral to organic ratio differs at 30%. INTRODUCTION Bone consists of two major components; an inorganic or mineral phase, which is a carbonated form of a finely crystalline calcium phosphate closely resembling hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 , (bone apatite - BAP), and an organic phase which is made up mainly of type I collagen fibers (COL). Bone tissue also includes water and organic molecules, such as glycosaminoglycans, glycoproteins, lipids, peptides and enzymes. Ions such as sodium, magnesium, fluoride and citrate are also present, as well as hydrogenophosphate. Traditional tools used in assessing the chemical composition of bone include electron microscopy, X-ray diffraction and wet chemical analysis. Use of these techniques has been proved time-consuming and cumbersome. Furthermore, during application the tissue is exposed to stresses that can alter its structure and/or its composition. The ideal analytical tool would be one in which minimal tissue preparation is required, while no loss of the amount and quality of information and sample is noted. Fourier Transform Raman Spectroscopy is becoming applicable as analytical technique for biomedical applications because: (a) The need for tissue preparation is minimal, the measurement itself is non- destructive to the tissue and very small amounts of material can be successfully analyzed. (b) Molecular (ultra structural) level information is available, allowing investigation of functional groups, bonding types and molecular conformations [1-3]. This study investigates the composition of cortical and trabecular bovine bone tissue by comparing the mineral to organic material Raman signal ratio.