Osteoblast attachment to hydroxyapatite micro-tube scaffolds

Abstract

Tissue engineering offers a novel route for repairing damaged or diseased tissue by incorporating the patient’s own healthy cells or donated cells into temporary scaffolds that act as a matrix for cell cultivation. Tissue scaffolds that are biocompatible and are porous with interconnected porous channels for cell ingrowth with a suitable degradation rate would be advantageous. In this study hydroxyapatite micro-tubes produced using the biomimetic coating technique will be pressed into a tissue scaffold. A compaction and sintering study will be done to observe appropriate pressure and heat treatment to produce a mechanically stable scaffold material. The ideal pressure was found to be 2.5 MPa where the tube-like structure was maintained, high porosity was achieved and suitable strength was possible. Sintering between 1,000 and 1,100 °C was found to produce good results. The average porosity for the chosen pressure of 2.5 MPa was 68 %. The scaffold was observed with SEM, micro tomography (micro-CT), chemical analysis and degradation testing. Porous channels were established using micro-CT where the porous channels were roughly 100 µm. Chemical analysis showed constant release of calcium and phosphorous, and far below toxic levels of heavy metals from the die. Degradation testing showed high degradation compared to tested commercially available materials. Cell culturing was done on the scaffold to characterise the biological performance of the scaffolds. Cell culturing was done in a 7 and 24 day cell culture to examine cell morphology and cell ingrowth. The results showed cell ingrowth into a micro-tube and cell orientation in a longitudinal direction. SEM, confocal microscopy and histology were employed as characterisation tools for observing cell ingrowth.