Robot-Assisted Precise Manufacturing of Tissue Spheroid in Single-Cell Scale

In three-dimensional cell culture, cells have the potential to form multicellular tissue spheroids through self-organization, which can be used to study human development and disease in-vitro, and to screen drugs for toxicity and efficacy. Current approaches are limited by intensive manual manipulation, and the uneven cell distribution caused by sedi-mentation, aggregation, and compaction of cells in bioprinting will affect the consistency of spheroid. Here, we develop an automated micromanipulation platform to control the consistency of the initial state and generate uniform cell clusters. To control spheroid formation, the implementation of such a system is dominated by real-time count of moving cells in micropipette, and the dynamic control of cells moving with a randomly distributed probability density. As an example application, we seeded 293T cells in microcavity. The accuracy of total cell count of the closed-loop system reached 95.47%. Additionally, the system was shown to be effective in preventing cell overflow. F or formed cell spheroids, the system prevented the creation of companion spheroids and improved spheroid consistency from 68.74% to 91.04%. This platform facilitates the use of spheroids for a wide range of biomedical applications such as organ development and precision drug screening.