Porous-interconnected cell microspheres-based 3D bioprinting of vascularized high-cell-density tissues with channel-pore networks

Natural tissues are characterized by critical physiological features, such as high-cell-density, heterogeneous cell coordination, and complex vascular networks, to perform series physiological functions. However, current tissue engineering models face challenges in achieving the three-dimensional integration of these characteristics, leading to an inability to accurately replicate the physiological functions of natural tissues. This study proposes an assembly model of porous network-interconnected cell microspheres (PICMs), utilizing L02 loaded high-cell-density microspheres as structural units combined with porous bioinks (GelMA/PEO), which not only preserves the inherent advantages of cell microspheres, including efficient mass transfer and dense intercellular interactions, but also allowing for controllable assembly of heterogeneous cells. Combining embedded 3D bioprinting, high-cell-density artificial tissues with vascular channel-pore networks can be precisely fabricated. The high permeability of the channel-pore networks meets the early metabolic demands of centimeter-scale artificial tissues with high-cell-density. Meanwhile, by integrating a perfusion culture platform and shear force stimulation, endothelial cells are introduced to directionally migrate and form a global macro-microvascular network, ensuring the long-term mass transfer efficiency of the artificial tissue. Ultimately, a bionic artificial liver tissue characterized by high-cell-density, heterogeneous cell composition, and vascularization was successfully fabricated. This study provides a novel pathway for constructing artificial organs with complete physiological functions.