Nano-biomaterials for designing functional bioinks towards complex tissue and organ regeneration in 3D bioprinting

The complexity of biological architectures (tissue or organ) attracts extensive use of additive manufacturing techniques for tissue engineering scaffolding. A step forward, to ensure precise control over the architecture-based distribution and activities of cells, cell-laden 3D bioprinting is in focused research at present for the regeneration of the tissue or organ. The process should ensure maximum viability and minimum stress for the encapsulated cells before, during and after printing. Thus, the printing properties of the bioinks are often compromised, and printing multilayered, large, complex organ with reasonably good resolution becomes a challenging task. Nanocomposite bioinks have caught scientists’ attention considering this aspect. Along with the structural stability and shape fidelity improvement during and after printing, the controlled use of nano-biomaterials induces differentiation, enhances cell growth, proliferation and extracellular matrix factor secretion. In this review, we have highlighted the significant importance of bioactive nanomaterials in bioinks for 3D bioprinting processes to overcome the limitations of native hydrogel-based bioinks. We have reviewed recent advances in the bioink components and compositions where different nano-biomaterials have been used to impart or improve physico-chemical, biological and printing properties. The designs of specific, functional nano-biomaterials -incorporated bioinks in regeneration of complex tissues, the steps towards large organ printing and future possibilities are addressed in the researchers’ interest.