Fabrication And Properties Of Hydroxyapatite/Nano-Cellulose Composites

Bone biomimetic tissue engineering is a promising fabrication method for the artificial bone materials. Recently, the hydroxyapatite(HAP)/organic polymer composites for the bone rehabilitation have been developed rapidly. Nano cellulose(NC) is a kind of natural organic polymer with good mechanical properties and biocompatibility. The HAP/NC composite was fabricated by the biomimetic method.The NC matrix was produced by static cultivation and the different cultivation conditions on the output of NC were investigated. The NC output had the direct relation with the cultivation time. When the cultivation temperature reached 30 oC, biological enzyme had high activeness, thus the NC output was higher. Additionally, the structure characters of NC were also studied by SEM, XRD and FTIR. NC had the fine network structure with a fiber diameter of around 5 nm. The hydroxyl and aether bonds existed in the molecular structure which contributed to the formation of the network.The HAP/NC composite which was fabricated through calcium pretreatment and biomimetic route had a dense sediment layer, and the pellet particles distributed on both the surface and the inside. The crystals were carbonate-containing apatites with low crystallite size and crystallinity, which had the similar crystal structure to the bone. Phosphorylation attached phosphate groups to the cellulose by esterification, and improved the matrix's ability to form apatite. The particles distributed equally on the surface of the HAP/pNC composite and the holes between the fibers were larger.The HAP/NC composites possess good biocompatibility. They are novel bone substitution materials with great potentials.