Radiation demineralised bone enhanced osteoinductive capacity after transplantation G.O. Phillips a,b, * , S. Al-Assaf a , P.A. Williams c , A. du Plessis d , C.J. Yim e a The Glyn O. Phillips Hydrocolloids Research Centre, North East Wales Institute, Mold Road, Wrexham LL11 2AW, North Wales, UK b Phillips Hydrocolloid Research Ltd., 45 Old Bond Street, London W1S 4AQ, UK c Centre for Water Soluble Polymers, North East Wales Institute, Mold Road, Wrexham LL11 2AW, North Wales, UK d Gammatron (PTY) Ltd., P.O. Box 26378, Monument Part 0105, South Africa e The School of Dentistry, Dankook University, Republic of Korea Available online 8 September 2007 Abstract Using a mediating alkyne gas during the radiation treatment prevents the degradation of natural and synthetic polysaccharides and proteins. The product has higher viscosity and is more elastic than the original material and, therefore, gives enhanced functionality. Protein, within demineralised bone, too can be modified to give enhanced osteoinductive capacity after transplantation. Thus new func- tionalities can be achieved from the new products produced in food and medical products. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Radiation; Polysaccharides; Cross-linking; Demineralised bone; Collagen; Molecular weight 1. Introduction Previously a radiation process was described which in the presence of an acetylenic gas enables the cross-linking of polysaccharides, protein and interactive blends [1,2]. The process was shown to allow the production of a tai- lor-made and reproducible products and so be offered as a unique material capable of being offered to enhance the functionality for their existing application or for new appli- cations which were not possible to achieve. Human bone, when treated by a process for the differen- tial removal of bone mineral, yields demineralised bone matrix (DBM) which has been shown to have the capacity to actively induce new bone [3]. The sequence of events that follow implantation of a DBM graft in vivo, has been well described [4]. Induction of new bone is due to bone morphogenetic proteins (BMP) within the matrix, while the non-BMP fraction of the matrix may have a passive role in retaining the BMP at the site of implantation, although it is not essential for the formation of new bone. Demineralisation leads to eas- ier release of the BMP. The first step in the action of DBM is the differentiation of the proliferated mesenchymal cells at the implant site into chondroblasts, evidenced by the synthesis of type II collagen and cartilage proteoglycans [5]. This period of chondrogenesis takes approximately four days. Over the next three days (8–10 days post implan- tation) the cartilage begins to mineralise and vascularisa- tion of the graft begins. At this point osteoblasts and osteoclasts are seen at the graft site. Alkaline phosphatase activity and calcium uptake increase, indicating the begin- ning of osteogenesis. The osteoblasts start making new mineralised bone, whilst the osteoclasts resorb the minera- lised cartilage. Over the next weeks an ossicle of new bone is formed. Consequently, such DBM material has wide application in oral and maxillofacial surgery, since the osteoinductive capacity of such allogeneic bone has the ability to form new bone by transforming the primitive 0168-583X/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2007.09.011 * Corresponding author. Address: The Glyn O. Phillips Hydrocolloids Research Centre, North East Wales Institute, Mold Road, Wrexham LL11 2AW, North Wales, UK. Tel.: +44 29 20 843298; fax: +44 29 20 843145. E-mail address: phillipsglyn@aol.com (G.O. Phillips). www.elsevier.com/locate/nimb Available online at www.sciencedirect.com Nuclear Instruments and Methods in Physics Research B 265 (2007) 390–393 NIM B Beam Interactions with Materials & Atoms