(502f) SIBLING Protein Induced Biomineralization

SIBLING Protein Induced Biomineralization

Native bone tissue is composed of a matrix of collagen,
non-collagenous proteins, and mineral, mostly hydroxyapatite (HAP). Bone
sialoprotein (BSP), osteopontin (OPN), and dentin phosphoprotein (DPP) are all
members of the SIBLING (small integrin-binding ligand, N-linked glycoprotein)
family of proteins, which are primarily found in mineralized tissues. In this
work, the mineralization induction capabilities of BSP, OPN, and DPP are
explored. Radiolabeled adsorption isotherms were constructed for BSP, OPN, and
DPP on a biomimetic collagen substrate. 
The results showed that BSP exhibited the highest binding capacity for
collagen, followed by DPP, and then OPN. The adsorption isotherms were then
used to study the effects of equal amounts of adsorbed proteins on a collagen
substrate with respect to HAP formation and morphology. Mineralization studies
were performed, and the adsorption isotherms were used to determine solution
concentrations that would result in equal amounts of adsorbed protein for each
of the three proteins. Substrates were placed in simulated body fluid for 5h,
10h, and 24h in an incubation chamber at 37 ^oC.
Photochemical assays were performed on demineralized substrates to determine a
Ca/P ratio for minerals formed with each of the proteins used at all time
points considered. Additionally, SEM images were taken of the substrates to
provide a qualitative comparison of mineral surface coverage at each time
point.