High Surface Area

The Effect of Increased Surface Area w.r.t Bioactivity

The Surface area of any Osteoconductive Biomaterial is an important characteristic as its assists the vascularization of the site (improved blood flow) and maintains osteocyte preservation for accelerated healing rates.

Surface area of bone is dependent on the grain boundary area and the smaller grain size of the hydroxyapatite crystals. High Surface Area bioceramics can be considered as nano composites as crystals are in the nanometer range. Increased grain boundary area results from the smaller grain size of the hydroxyapatite crystals.

What are the Benefits?

The Higher Surface Area of the bioceramic results in an increased proliferation of bone cells compared to conventional hydroxyapatite bioceramics according Ian Smith et al, Int Journal of Nanomedicine 2006:1(2) 189–1942006.

Why does Bone Cell Proliferate on High Surface Area Biominerals?

A possible explanation is that the quantity of proteins adsorbed on particles positively correlates with their specific surface area. Nanosized particles adsorbed significantly greater amounts of proteins, and induced enhancement of subsequent cell adhe¬sion and proliferation during the bone regeneration process.

The basis for Osteobalstic–HA adhesion and the effect of grain boundary volume on Osteoblastic behaviour are not completely understood, but may be linked in part to protein interactions at the surface. Cai et al found that a decrease in grain size promoted an increase in vitronectin and collagen concentration and a decrease in albumin, laminin, and fibronectin concentrations (Cai,Y et al, J.Mater Chem, 2007,17, 3780-3787)

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