Bone putty bioimplant improvement: evaluation of the influence of surface area and shape of the DBM (demineralised bone matrix) component on bone induction and biocompatibility properties of carrier (polymer)/demineralised bone matrix

Using demineralised bone matrix (DBM) grafts is one of common treatments for bone end stage disease. One of the best products in this field is putty created by adding a carrier to the DBM powder which makes it malleable. However, this can lead to reduced osteoinductivity of the graft, as compared with the original DBM. Other disadvantage of currently used water soluble carriers is their water solubility, which can result in release of DBM particles from the graft site or disaggregation of DBM before regeneration. The aim of this project is to increase the osteoinductivity of DBM putty and to improve its mechanical properties, in order to prevent DBM wash-out and allow better graft fixture to the bone. This project will formulate and test polymeric bi-component carriers (Alginate base) capable of hardening in situ and becoming insoluble. Their performance will be compared with Carboxymethyl Cellulose base carrier. In addition, the project wills trial DBM samples of varying particle sizes and shapes. • powder with particle size 150-500 μm • powder with particle size 500-1000 μm • fibres 600 micron thick of variable lengths In this project by using in-vitro osteoblastic like cell culture model, the samples was tested for its ability to induce bone cell growth and assessed with qPCR for osteonectin, osteopontin and osteocalcin mRNA quantitative expression. The samples were tested in different group in accordance to DBM and carrier type. The cytotoxicity test results (p< 0.05) show that all newly formulated bone putty samples are biocompatible. The data also confirms that all groups are capable of supporting the in vitro growth and maturation of osteoblasts-like cells. There is up-regulation of bone formation specific mRNA especially in the powder particle sizes 150-500 μm and in fibre samples. Also, the carrier had an effect on qPCR results although more assessment needs to be done in order to confirm this finding.