Kaolin-reinforced 3D MBG scaffolds with hierarchical architecture and robust mechanical strength for bone tissue engineering

Abstract

Three-dimensional mesoporous bioglass (3D MBG) scaffolds with mesoporous structures and highly interconnected macroporous networks are considered as ideal biomaterials for skeletal tissue applications. However, their inherent brittleness and poor mechanical strength greatly hamper their performance and clinical application. Here, using a modified polyurethane foam (PU) templating method with utilization of kaolin as binder, a new facile method for preparation of 3D MBG scaffolds with excellent mechanical strength, mineralization ability and desirable cellular response is proposed. The developed hybrid MBG-XK (where X refers to the final dry weight of kaolin in the scaffold) scaffolds with 85% porosity exhibited a high compressive strength from 2.6 to 6.0 MPa with increasing content of kaolin (5–20%), about 100 times higher than that of the traditional PU-template MBG scaffold. With the addition of kaolin, the MBG-10K scaffold exhibited a more stable and desirable pH environment, and an enhanced protein adsorption capacity. Furthermore, with rat bone marrow stromal cells as a model, in vitro cell culture experiments indicated that, compared with MBG, the prepared MBG-XK scaffolds possessed comparable cell proliferation, penetration capacity, enhanced cell attachment and osteogenic differentiation, especially for MBG-10K.