Gelatin/hydroxyapatite nanocomposite scaffolds for bone repair

The use of bioscaffolds for tissue repair is widely accepted. They can provide structural stability and a 3D system on which cells can grow new tissue. Natural bone is composed of organic (mainly collagen) and mineral biomaterials (predominantly carbonate hydroxyapatite, HA). In recent years, developments in 3D porous-scaffold manufacturing have increased hopes of successful fabrication of structures with ever closer similarities to bone matrix. Thus, most widely investigated composites for engineering tissue scaffolds are composed of natural polymers reinforced with HA ceramic particles.1–4 Gelatin (GEL), a derivative of collagen, is an attractive component for extracellular-matrix replacement, since it contains several biological functional groups that enhance osteoblast adhesion, migration, and mineralization.5 A few years ago, synthesis of GEL/HA nanocomposites for bonetissue engineering was the main focus of a number of research groups. It was shown that, in addition to the chemical structure of bioscaffolds, other properties—such as their porosity and texture (especially on microand nanoscales)—can dramatically influence the nature of the cellular reaction to the material.6 Our aim was to design and fabricate a close-to-ideal scaffold for bone-tissue repair and study the effects of different glutaraldehyde (GA) concentrations as cross-linking agent. We synthesized nanocrystalline HA powders through precipitation7 and, combining them with GEL, engineered a 3D nanocomposite scaffold. Our emphasis was on achieving uniform and proper pore size and increased scaffold strength, comparable with the mechanical characteristics of bone tissue. To engineer nanocomposite scaffolds, we prepared a homogeneous aqueous solution of microbiology-grade GEL (10% weight per volume, w/v) and added our synthesized HA nanopowder to obtain a GEL(70)/HA(30) weight composition. After Figure 1. Scanning-electron micrograph of fabricated gelatin/hydroxyapatite nanocomposite scaffold.