Availableonlineatwww.sciencedirect.com SCIENCE DIRECT R materials letters ELSEVIER Materials Letters 59(2005)69-7 www.elseviercomlocate/matlet Microstructure and osteoblast adhesion of continuously porous Al2O3 body fabricated by fibrous monolithic process In-Cheol Kang, Taek -Soo Kim, Kwang-Kjune Ko, Ho-Yeon Song Takashi Goto, Byong-Taek L 182 Shinkwan-dong, Kongju, Chungnam 314-701, Republ Department of Microbiology, School of Medicine, Soonchunhyang University, 366-1 Ssangyoung-don m, Chungnam 330-090, Republic of Korea Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Japa Received 22 March 2004: received in revised form 14 September 2004: accepted 18 September 2004 Available online 5 October 2004 Abstract e. Continuously porous AlO, body was fabricated by a fibrous monolithic process. It was relatively easy and convenient to control the rostructure as well as the shape and size of pores. With increasing the passes of process, the size of pores was reduced corresponding to the extrusion ratio. The resultant sizes of continuous pore formed in the second and third passed bars were 200 and 40 um in diameter, respectively. In order to investigate a biocompatibility of the porous Al2O, body, in vitro test was performed using a human osteoblast-like MG-63 cells. It was seen that the cells were well attached and grown on the Al2O3 porous body fabricated by fibrous monolithic process. C 2004 Elsevier B V. All rights reserved. Keywords: Continuously porous Al,O3; Fibrous monolithic process; Microstructure control; In vitro test 1. Introduction artificially and naturally made. The porous bioinert ceramic has also been known to form a thinner fibrous layer with It is known that Al2O3 is a typical bioinert ceramic which faster hilling in surrounding muscles and connective tissues as been widely used in total hip prosthesis and dental compared with the dense ones [5]. The bone in human body implants due to its good biocompatibility, high strength, and is made up of two types of structures as outer thin-walled excellent corrosion and wear resistance [1-3. Especially, compact bone and inner cancellous( spongy) bone. The polycrystalline a-Al2O3 having grain size less than 7 um, latter consists of a three-dimensional lattice of trabeculae, tensity higher than 3.90 g/cm, and purity higher than and the porous structures in the cancellous bone are 99.5% was required to use clinically by the International necessary for the formation of bone marrow and the growth Standard Organization (ISo)[4]. of bone. Suitable pore size was reported to be approximately The bioinert ceramic implants exhibited, however, a 100-150 [5], 140-160 [6], and 200-1000 um [7]. In fibrous encapsulation, which limits a chemical and mechan- addition, Al2O3 was reported to form the thinnest fiber ical combining between the implant and natural bone. Thus, layer along the surface compared with other bioinert research on the bioinert ceramics has been focused on the ceramIcs porous structure because the porous structure provides an It has been reported that there are several methods interlocking and then diminishes motion between the bones fabricating the porous Al2O3 such as sintering [9, 10], hot isostatic pressing [11], and microwave sintering[12].Those processes usually used a mixture of a pore-forming agent Tel: +82 41 850 8677: fax: +82 41 2939. such as carbon, polymer, etc. and the Al2O3 powder, and guac kr(B.-T. Lee). then removed the agent. Thus, those are relatively compli 0167-577X/S- see front matter o 2004 Elsevier B V. All rights reserved doi:10.1016/ malet.2004.09.019Microstructure and osteoblast adhesion of continuously porous Al2O3 body fabricated by fibrous monolithic process In-Cheol Kanga , Taek-Soo Kima , Kwang-Kjune Kob , Ho-Yeon Songb , Takashi Gotoc , Byong-Taek Leea, * a Chungnam Research Center for Nano Materials and School of Advanced Materials Engineering, Kongju National University, 182 Shinkwan-dong, Kongju, Chungnam 314-701, Republic of Korea b Department of Microbiology, School of Medicine, Soonchunhyang University, 366-1 Ssangyoung-dong, Cheonan, Chungnam 330-090, Republic of Korea c Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Japan Received 22 March 2004; received in revised form 14 September 2004; accepted 18 September 2004 Available online 5 October 2004 Abstract Continuously porous Al2O3 body was fabricated by a fibrous monolithic process. It was relatively easy and convenient to control the microstructure as well as the shape and size of pores. With increasing the passes of process, the size of pores was reduced corresponding to the extrusion ratio. The resultant sizes of continuous pore formed in the second and third passed bars were 200 and 40 Am in diameter, respectively. In order to investigate a biocompatibility of the porous Al2O3 body, in vitro test was performed using a human osteoblast-like MG-63 cells. It was seen that the cells were well attached and grown on the Al2O3 porous body fabricated by fibrous monolithic process. D 2004 Elsevier B.V. All rights reserved. Keywords: Continuously porous Al2O3; Fibrous monolithic process; Microstructure control; In vitro test 1. Introduction It is known that Al2O3 is a typical bioinert ceramic which has been widely used in total hip prosthesis and dental implants due to its good biocompatibility, high strength, and excellent corrosion and wear resistance [1–3]. Especially, polycrystalline a-Al2O3 having grain size less than 7 Am, density higher than 3.90 g/cm3 , and purity higher than 99.5% was required to use clinically by the International Standard Organization (ISO) [4]. The bioinert ceramic implants exhibited, however, a fibrous encapsulation, which limits a chemical and mechan￾ical combining between the implant and natural bone. Thus, research on the bioinert ceramics has been focused on the porous structure because the porous structure provides an interlocking and then diminishes motion between the bones artificially and naturally made. The porous bioinert ceramic has also been known to form a thinner fibrous layer with faster hilling in surrounding muscles and connective tissues compared with the dense ones [5]. The bone in human body is made up of two types of structures as outer thin-walled compact bone and inner cancellous (spongy) bone. The latter consists of a three-dimensional lattice of trabeculae, and the porous structures in the cancellous bone are necessary for the formation of bone marrow and the growth of bone. Suitable pore size was reported to be approximately 100–150 [5], 140–160 [6], and 200–1000 Am [7]. In addition, Al2O3 was reported to form the thinnest fiber layer along the surface compared with other bioinert ceramics [8]. It has been reported that there are several methods on fabricating the porous Al2O3 such as sintering [9,10], hot isostatic pressing [11], and microwave sintering [12]. Those processes usually used a mixture of a pore-forming agent, such as carbon, polymer, etc. and the Al2O3 powder, and then removed the agent. Thus, those are relatively compli- 0167-577X/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2004.09.019 * Corresponding author. Tel.: +82 41 850 8677; fax: +82 41 858 2939. E-mail address: lbt@kongju.ac.kr (B.-T. Lee). Materials Letters 59 (2005) 69 – 73 www.elsevier.com/locate/matlet