Recent advances on bioprinting of hydrogels containing carbon materials

The intrinsic properties and versatility of carbon materials (CMs) have recently raised a growing interest in their combination with hydrogels towards the development of advanced materials for biomedical applications. The increasing demand for biomimetic constructs that closely mimic the intricate composition and structure of native tissues has boosted the interest in using three-dimensional (3D) bioprinting technologies for the processing of CMs-containing hydrogels into specialized and more complex constructs capable of steering cell behavior. This review summarizes the progress on the bioprinting of 3D hydrogels containing CMs, focusing on the role of CMs on biomaterial ink design and their impact on both the printing process and the biological function of fabricated constructs. Recent findings demonstrate that CMs are versatile materials that have been mostly used to (1) tune the rheological properties of biomaterial inks, (2) improve the mechanical properties of hydrogels, and/or (3) confer new physical features to hydrogels, such as shape memory, roughness, and thermal and electrical conductivity, which have been shown to modulate the biological response of bioprinted constructs.