Memoirs of the Faculty of Engineering,Okayama UniversitY,Vo1.29, No.2, pp.83-88, March 1995 Effect of Alcohol on Bioactivity of Glasses Kanji TSURU*, Chikako NISHIYAMA*, Chikara OHTSUKI* and Akiyoshi OSAKA* (Received January 27 , 1995) One of the CaO,Si0 2 -based bioactive glasses(5OCaO' .5OSi0 2 in mol%) were soaked for various periods in a simulated body fluid(SBF) with or without containing alcohols such as methanol, ethanol, and I-propanol. Effect of the alcohols was investigated on the apatite formation on the glass surface with thin-film X-ray diffraction, Fr-IR reflection spectroscopy and scanning electron microscopy. Under the presence of alcohols up to O.lmol/l in the SBF an apatite layer was formed on the glass, while it consisted of crystallites similar in morphology but larger in size than that found for the SBF without the alcohols. It was concluded that the alcohols little influenced the the apatite forming ability of the CaO,SiOTbased glasses. 1. INTRODUCTION Since discovery of Bioglass® by Hench et ai. in the early 1970s1), various types of glasses and glass-ceramics have been developed that can bond to living bone. Some of them are already clinically used as valuable bone substitutes such as artificial middle ear bones, alveolar ridge maintenance implants, artificial iliac crests and vertebrae 2 )-4), etc. These bioactive glasses and glass-ceramics, however, can not replace a whole piece of femur and tibia, because fracture toughness is lower and Young's modulus is higher than that of the human cortical bone. One may consider obtaining bioactive materials with high fracture toughness by incorporating bioactive glass powders into an organic polymer with sol-gel methods. Bioactive composite materials prepared with the sol-gel methods would contain residual alcohols that are used during preparation. However, the effect of alcohols on bioactivity of glasses has not been revealed yet. It has been already confirmed5) that the essential condition for various kinds of glasses and glass-ceramics to bond to living bone is the formation of a biologically active bone-like apatite layer on their surfaces when they are embedded in the body, and that the apatite layer is reproduced on the surfaces of bioactive glasses and glass-ceramics even in an acellular simulated body fluid(SBF). Moreover, the binary system CaO-Si0 2 gives the simplest composition showing bioactivity6),7). In the present study, in order to reveal the effect of alcohols on bioactivity of glasses, the apatite formation on the surface of .5OCaO' .5OSi0 2 (mol%) glass is thus investigated in the SBF containing alcohols. 2. EXPERIMENTAL PROCEDURE 2.1. Preparation of .5OCaO· .5OSi 02(mol %) A glass of the nominal composition .5OCaO·.50Si0 2 (mol%) was prepared by melting a mixture of appropriate amounts of reagent-grade chemicals Caco 3 and Si0 2 with a 30ml platinum crucible at 1600 °C for 1 h in an MoSi 2 electric furnace. The melt was poured on to a stainless steel plate to be formed into a plate about Imm thick, and allowed to cool in an SiC furnace from 700 °C. Rectangular specimens of 15xlOxi mm 3 were cut from the obtained *Department of Bioengineering Science 83