Macrophage response to biomaterials

Macrophages are key players of the biological response to implanted biomaterials, in the process of biomaterial-tissue integration and on the subsequent tissue repair. Macrophages are remarkable plastic cells that can shift from one phenotype to another. In tissue engineering and regenerative medicine, after implantation of a biomaterial or biomedical device, it is desirable to have control over the M1–M2 phenotype progression and to ensure a timely and smooth transition from the inflammatory to the healing stage. As such, several immunomodulatory strategies, focused on the macrophage, have been developed in an attempt to modulate immune responses that include different approaches such as the modification of the chemical or physical properties of the materials, the combination of bioactive molecules that can be antiinflammatory drugs, pro-resolution mediators, or growth factors, and cell therapy methods either by including immune cells or by inducing their recruitment.