Towards in vivo application of oxygen-releasing microspheres for enhancing bone regeneration

A lack of bone tissue can have several causes, for example a fracture or an infection. To fill bone voids, bone from elsewhere in the patient’s own body can be used. However, there is not much bone available to do this. Artificial materials are also used to fill bone voids. These artificial materials are often combined with cells that are able to form bone tissue. Unfortunately, there are no blood vessels within artificial bone replacement materials. Because of this, cells seeded on a bone replacement material suffer from an insufficient blood supply, so they do not receive sufficient amounts of oxygen. Due to this lack of oxygen cells often do not survive for a long time and die, and thus no new bone tissue is formed.
Oxygen-releasing microspheres have been developed to improve the oxygen supply to bone cells that are attached to an artificial bone replacement material. These microspheres release oxygen for about three weeks. In laboratory tests and in tests in mice it was shown that the body does not reject the microspheres. To test the effect of the microspheres, they were implanted in mice under a skin flap of which most of the blood vessels were cut through. The skin flaps under which oxygen-releasing microspheres had been implanted showed less tissue death than the skin flaps under which non-oxygen-releasing microspheres had been implanted. The effect of the oxygen-releasing microspheres on bone recovery has not been investigated yet.