Technological watch

Bioactive materials developed through three-dimensional (3D) bioprinting technology exhibit static nature and don't respond to the dynamic changes occurred in the human body micro-environment. With the development of stimuli-responsive materials (SRMs) especially shape memory polymers (SMPs), a novel technology “four-dimensional (4D) bioprinting” was recently gaining attention in the biomedical sector. It involves remodeling and maturing of the 3D-printed (3DPed) tissues. The fundamental objective of the 4D bioprinting (4DBP) technology is to develop intricate tissue constructs which possess inherent features of transforming their shape and characteristics through a variety of physical, chemical, or biological stimuli and help in regrowing, repairing, or replacing traumatized tissues, cells, or organs. Considering the market trends of 4DBP technology it is essential to present a state-of-the-art review containing different types of SRMs and bioprinting technologies. Moreover, this review also incorporates different bioactive materials applied in different soft and hard tissue engineering (TE) applications. This review also illustrates current challenges which will pave the way for possible future developments in the TE field. Finally, it is anticipated that 4DBP technology will completely revolutionize the biomedical sector in the near future.