Advances in 3D-bioprinted implantable liver microtissue for liver failure treatment.

Liver failure represents a significant global health challenge, and orthotopic liver transplantation remains the only available clinical therapy for this disease. However, the severe shortage of donor organs has made the development of alternative therapies for liver function replacement an urgent unmet clinical need. Over the past decades, regenerative medicine and tissue engineering research have been dedicated to developing engineered synthetic tissues and organs for transplantation. As an advanced and prospective biofabrication technique, three-dimensional (3D) bioprinting offers an innovative approach to fabricate implantable biomimetic liver microtissues. This review summarizes the latest research progress in 3D-bioprinted liver microtissues, covering bioink selection, cellular source options, and key fabrication technologies, as well as vascularization strategies. In addition, commonly used in vitro and in vivo evaluation metrics for therapeutic efficacy are discussed. Finally, the current challenges and future prospects in this field for clinical translation are highlighted.