title: The incorporation of strontium and zinc into a calcium-silicon ceramic for bone tissue engineering.
abstract: In this study we developed novel scaffolds through the controlled substitution and incorporation of strontium and zinc into a calcium-silicon system to form Sr-Hardystonite (Sr-Ca(2)ZnSi(2)O(7), Sr-HT). The physical and biological properties of Sr-HT were compared to Hardystonite (Ca(2)ZnSi(2)O(7)) [HT]. We showed that Sr-HT scaffolds are porous with interconnected porous network (interconnectivity: 99%) and large pore size (300-500 microm) and an overall porosity of 78%, combined with a relatively high compressive strength (2.16+/-0.52 MPa). These properties are essential for enhancing bone ingrowth in load-bearing applications. Sr-HT ceramic scaffolds induced the attachment and differentiation of human bone derived cells (HOB), compared to that for the HT scaffolds. Sr-HT scaffolds enhanced expression of alkaline phosphatase, Runx-2, osteopontin, osteocalcin and bone sialoprotein. The in vivo osteoconductivity of the scaffolds was assessed at 3 and 6 weeks following implantation in tibial bone defects in rats. Histological staining revealed rapid new growth of bone into the pores of the 3D scaffolds with the Sr-HT and HT, relative to the beta-tricalcium phosphate (beta-TCP). In vivo, HT and Sr-HT produced distinct differences in the patterns of degradation of the materials, and their association with TRAP positive osteoclast-like cells with HT appearing more resistant compared to both Sr-HT and beta-TCP.
authors.affiliation: Biomaterials and Tissue Engineering Research Unit, School of AMME, The University of Sydney, Sydney, NSW 2006, Australia. hzreiqat@usyd.edu.au
authors.forename: Hala
authors.initials: H
authors.lastname: Zreiqat
authors.forename: Yogambha
authors.initials: Y
authors.lastname: Ramaswamy
authors.forename: Chengtie
authors.initials: C
authors.lastname: Wu
authors.forename: Angelo
authors.initials: A
authors.lastname: Paschalidis
authors.forename: ZuFu
authors.initials: Z
authors.lastname: Lu
authors.forename: Barbara
authors.initials: B
authors.lastname: James
authors.forename: Oliver
authors.initials: O
authors.lastname: Birke
authors.forename: Michelle
authors.initials: M
authors.lastname: McDonald
authors.forename: David
authors.initials: D
authors.lastname: Little
authors.forename: Colin R
authors.initials: CR
authors.lastname: Dunstan
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001483:Base Sequence; D001846:Bone Development; D001842:Bone and Bones / Q000378:metabolism; D002478:Cells, Cultured; D050676:Core Binding Factor Alpha 2 Subunit / Q000378:metabolism; D017931:DNA Primers; D006801:Humans; D058574:Integrin-Binding Sialoprotein; D015675:Osteocalcin / Q000378:metabolism; D053495:Osteopontin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000378:metabolism; D013324:Strontium / Q000737:chemistry*; D023822:Tissue Engineering; D015032:Zinc / Q000737:chemistry*
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D017931:DNA Primers; C546871:IBSP protein, human; D058574:Integrin-Binding Sialoprotein; C493728:RUNX1 protein, human; D012795:Sialoglycoproteins; D015675:Osteocalcin; D053495:Osteopontin; D000469:Alkaline Phosphatase; D015032:Zinc; D013324:Strontium