Research progress in biomimetic gradient scaffolds for osteochondral tissue engineering

Abstract

Osteochondral defects are the main cause of joint morbidity and disability in elderly patients, and osteochondral tissue engineering is one of the methods to repair osteochondral defects. The method of osteochondral tissue engineering involves the manufacture of osteochondral biomimetic gradient scaffolds that should mimic the physiological properties of natural osteochondral tissue (e.g., the gradient transition between cartilage surface and subchondral bone). The osteochondral biomimetic gradient scaffolds exhibit discrete gradients or continuous gradients to establish the characteristics of osteochondral tissue in many studies, such as biochemical composition, structure and mechanical properties. An advantage of the continuous osteochondral biomimetic gradient scaffold is that there is no obvious interface between each layer, therefore it more closely mimics the natural osteochondral tissue. Although promising results have been achieved so far on the regeneration of the osteochondral biomimetic gradient scaffold, there are still differences between the osteochondral biomimetic gradient scaffold and natural osteochondral tissue. Due to these differences, the current clinical treatment of osteochondral biomimetic gradient scaffolds to repair osteochondral defects needs further research. Firstly, the research progress on discrete and continuous gradient scaffolds from the background of osteochondral defects, the micro-scale structure and mechanical properties of osteochondral to the materials and methods related to the manufacture of osteochondral biomimetic gradient scaffolds was summarized in this article. Secondly, due to the 3D printing method of the osteochondral biomimetic gradient scaffold having the ability to precisely control the geometry of the scaffold hole and the mechanical properties of the scaffold, the application of computational simulation models in osteochondral tissue engineering was further introduced, for example, optimizing scaffold structure and mechanical properties are considered to predict tissue regeneration. Finally, the challenges related to the repair of osteochondral defects and prospects for the future research of osteochondral tissue regeneration were presented.For example, continuous osteochondral bionic gradient scaffolds need to more similarly simulate the structure of natural osteochondral tissue units, that is, the transition of mechanical properties and biochemical properties is more smooth naturally. At the same time, although most osteochondral biomimetic gradient scaffolds have achieved good results in in vivo and in vitro experiments, clinical research and application still need to be further studied.

Keywords

• osteochondral
• tissue engineering
• biomimetic gradient scaffold
• biomaterial
• 3d printing