The clinical significance of 4D printing

4D printing is the next step on from 3D printing involving the fourth dimension of 'time'. The programmed 4D-printed objects are capable of changing their shape in response to external stimuli, such as light, heat, or water, differentiating them from 3D-printed static objects. This technique promises new possibilities for cancer treatment, drug delivery, stent development, and tissue engineering. In this review, we focus on the development of 4D-printed objects, their clinical use, and the possibility of 5D printing, which could revolutionize the fields of biomedical engineering and drug delivery.