Medical application and prospect of 4D printing

4D printing, which distorts smart materials under specific stimulation, is emerging as a kind of modern fabrication technology. Underpinned by computer science and materialogy, 4D printing combines a wide range of disciplines including physics, bioengineering, medicine with manufacturing industry, and creates three-dimensional solid objects by adding smart materials layer by layer. Compared with 3D printing, 4D printing is functional demand-oriented, and the geometric structure formed by intelligent materials folds, bends, expands or shrinks under specific stimuli such as temperature and water, thus realizing the change of the performance of the object itself, such as hardness, stiffness, permeability and so on. 4D printing would serve as a new way of digital intelligent manufacturing, which emphasizes the need to consider the dynamic tissue healing and regeneration processes within human body. In addition, it can effectively realize the self-repair of the tissue and complete the bionics from structure to function, so it more truly simulates the dynamic evolution of human micro-environment. In this review, we collect the latest cases of 4D printing in biomedicines at home and abroad and then the potential advantages and challenges of 4D printing in practical application will be analyzed. Finally, we propose future directions and perspectives to further promote intelligentized 4D bioprinting technology in imitating architectures and function of native human tissues. DOI: 10.11855/j.issn.0577-7402.2021.06.11