Gelatin/Gelatin-modified nano hydroxyapatite composite scaffolds with hollow channel arrays prepared by extrusion molding for bone tissue engineering

Abstract

Abstract Bone tissue engineering scaffold has been successfully applied in the field of bone repair, but the major limitation is the delivery of oxygen and nutrients throughout the bulk of engineered tissue, especially for large scaffolds. Researchers have found that scaffolds with hollow channels can effectively solve this problem. We utilized a novel extrusion approach to prepare scaffolds with hollow channel arrays, which has the advantages of economy, continuous production, and high efficiency. The hollow channel scaffolds were composed of gelatin and gelatin-modified nano hydroxyapatite (nHAP). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and atomic force microscope (AFM) results indicate that the prepared gelatin-modified nHAP are nanorod-like particles with the length of 30∼50 nm and width of 5∼15 nm. The nano particle is composed of crystalline HAP grains with the size less than 10 nm and amorphous phases. A part of OH− or PO 4 3 − are replaced by CO 3 2 − during preparation process, leading to the transformation of HAP into hydroxyl-carbonated apatite (HCA). The prepared hollow channel scaffolds exhibit much better mechanical properties compared with the sponge porous scaffolds. The axial compressive strength of the hollow channel scaffold with porosity of 51.3 ± 5.2% can reach 25 ± 1.4 MPa, which can meet the mechanical strength requirement as an implant completely. Moreover, the hollow channel scaffold exhibited good in vitro degradability and bioactivity. These results highlight the potential of using gelatin/gelatin-modified nHAP composite scaffolds with hollow channels for bone tissue engineering.