Bioprinting of cellular aggregates, such as tissue spheroids, to form three-dimensional (3D) complex-shaped arrangements, has posed a major challenge due to lack of robust, reproducible and practical bioprinting techniques. Here, we demonstrate 3D aspiration-assisted freeform bioprinting of tissue spheroids by precisely positioning them in self-healing yield-stress gels, enabling the self-assembly of spheroids for fabrication of tissues. The presented approach enables the traverse of spheroids directly from the cell media to the gel and freeform positioning of the spheroids on demand. We study the underlying physical mechanism of the approach to elucidate the interactions between the aspirated spheroids and the gel’s yield-stress during the transfer of spheroids from cell media to the gel. We further demonstrate the application of the proposed approach in the realization of various freeform shapes and self-assembly of human mesenchymal stem cell spheroids for the construction of cartilage and bone tissues.

由于缺乏稳健、可重复且实用的生物打印技术，对细胞聚集体（例如组织球体）进行生物打印以形成三维（3D）复杂形状的排列已构成重大挑战。在这里，我们展示了组织球体的 3D 抽吸辅助自由形式生物打印，通过将组织球体精确定位在自愈屈服应力凝胶中，实现球体的自组装以制造组织。所提出的方法能够将球体直接从细胞介质横移到凝胶，并根据需要自由定位球体。我们研究了该方法的基本物理机制，以阐明在球体从细胞介质转移到凝胶期间，吸出的球体与凝胶屈服应力之间的相互作用。我们进一步证明了所提出的方法在实现各种自由形状和自组装人类间充质干细胞球体以构建软骨和骨组织中的应用。