周奎博士于2019.2-2020.3在宾夕法尼亚州立大学Ibrahim T. Ozbolat副教授课题组进行为期一年的访学，期间参与了Aspiration-assisted bioprinting的研究项目，相关成果近期被Communications Physics杂志接收。周奎博士主要负责论文的打印工艺部分。

Aspiration-assisted freeform bioprinting of pre-fabricated tissue spheroids in a yield-stress gel

Bugra Ayan, Nazmiye Celik, Zhifeng Zhang, Kui Zhou, Myoung Hwan Kim, Dishary Banerjee, Yang Wu, Francesco Costanzo, Ibrahim T Ozbolat*

https://www.nature.com/articles/s42005-020-00449-4

Abstract

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.