3D bioprinting strategy for engineering vascularized tissue models

Leveraging three-dimensional (3D) bioprinting in the fields of tissue engineering and regenerative medicine has rapidly accelerated progress toward the development of living tissue constructs and biomedical devices. Ongoing vigorous research has pursued the development of 3D in vitro tissue models to replicate the key aspects of human physiology by incorporating relevant cell populations and adequate environmental cues. Given their advantages of being able to intimately mimic the heterogeneity and complexity of their native counterparts, 3D in vitro models hold promise as alternatives to conventional cell cultures or animal models for translational application to model human physiology/pathology and drug screening. Research has highlighted the importance of in vitro models, and a sophisticated biomanufacturing strategy is vitally required. In particular, vascularization is critical for the prolonged survival and functional maturation of the engineered tissues, which has remained one of the major challenges in the establishment of physiologically relevant 3D in vitro models. To this end, 3D bioprinting can efficiently generate solid and reproducible vascularized tissue models with high architectural and compositional similarity to the native tissues, leading to improve the structural maturation and tissue-specific functionality. Multiple bioprinting strategies have been developed to vascularize in vitro tissues by spatially controlled patterning of vascular precursors or generating readily perfusable vascular structures. This review presents an overview of the advanced 3D bioprinting strategies for vascularized tissue model development. We present the key elements for rebuilding functional vasculature in 3D-bioprinted tissue models and discuss the recent achievements in the engineering of 3D vascularized in vitro models using 3D bioprinting. Finally, we delineate the current challenges and future outlooks of 3D bioprinting-based vascularized tissue models.