Advances in oxygen-releasing matrices for regenerative engineering applications

In recent years, the effects of hypoxia on tissue repair have received wider attention with the deepening of tissue engineering research. Various oxygen supply strategies have wider applications in the field of tissue repair. Currently, commonly used methods of oxygen supply for defective tissues include hyperbaric oxygen (HBO) and oxygen-releasing materials. Between them, oxygen-releasing materials continuously and efficiently release oxygen from within the defective tissue. Compared with HBO, which may cause oxidative stress in healthy tissues, supplying oxygen via oxygen-releasing materials is safer because of their oxygen-releasing in situ and specific oxygen supply characteristics. However, there still exist some problems in the study of oxygen-releasing materials, such as cytotoxicity and the shortage of oxygen-releasing time. The current reviews on oxygen-releasing materials mostly elaborate on the principles of oxygen-releasing materials and lack a review of their preparation methods and applications. In this paper, different types of oxygen-releasing materials, such as hydrogels, microspheres, and layers, are reviewed concerning their applications, structures, current development status, and challenges.