Gradient Organic Inorganic Nanocomposites for Tissue Repair at the Cartilage/Bone Interface
Damages to articular cartilage that are caused by trauma, age-related diseases (arthritis, arthrosis) and/or physical stress pose major medical problems. A possible solution is to introduce a biodegradable sponge-like scaffold containing cartilage-forming cells. In the current work we developed a model for a partially calcified functional biomedical membrane with a gradient of calcium phosphate crystal density to form the interface between bone and a sponge-like cell containing scaffold for cartilage regeneration. The membrane consists of a biocompatible, biodegradable, partially calcified hydrogel, in our case gelatin was used. One part is an organic-inorganic nanocomposite consisting of nanocrystalline calcium phosphate particles, formed in situ within the hydrogel, while the other part is the hydrogel without inorganic crystals. The experimental method used was one-dimensional single diffusion. Gelatin gels containing calcium or phosphate ions, respectively, were exposed from the upper side to a solution of the other constituent ion (i.e. a sodium phosphate solution was allowed to diffuse into a calcium containing gel and vice versa). Scanning electron microscopy (E-SEM), EDX, XRD and ATR-FTIR spectroscopy confirmed the existence within the gel of a density gradient of carbonate apatite crystals, with a dense top layer extending several microns into the gel. Ca/P atomic ratios were in the range characteristic of calcium deficient apatites. The effect of different experimental parameters on the calcification process within the gelatin membranes is discussed.
Eyup Sabri Kayali, Gultekin Goller and Ipek Akin
M. G. Aviv et al., "Gradient Organic Inorganic Nanocomposites for Tissue Repair at the Cartilage/Bone Interface", Key Engineering Materials, Vols. 493-494, pp. 577-581, 2012