ABSTRACT
An emerging technique, 4D bioprinting, has attracted more and more attention recently due to its potential applications in biomedical engineering and other fields. In this technique, time as the fourth dimension is integrated with 3D bioprinting; it considers not only the initial state of the bioprinted construct but also its evolution process with time. The printed objects (e.g., biocompatible materials, living cells, or even tissues) would change their shapes or functionalities when an external stimulus is imposed. In this chapter, we would discuss two types of 4D bioprinting, the first one is based on the deformation of stimulus-responsive materials, which leads to the self-deformation of printed objects. The second type refers to the one based on the cells’ development/maturation, which results in the cellular constructs with functionality such as nature tissues and with a particular shape due to cell assembling. One of the major merits of 4D bioprinting is that the printed object can evolve into a state that is difficult or even impossible to achieve with other methods. Based on its advantages, 4D bioprinting is considered as a promising solution to biomedical problems, such as tissue engineering (TE) and drug delivery.
