Abstract

On-Chip Vasculature for Engineering Three-Dimensional Cell Culture Environment of Spheroids and Organoids

Ryuji Yokokawa, Professor, Department of Micro Engineering, Kyoto University

In vivo, healthy vasculature has a hollow structure to supply oxygen and nutrients to tissues. However, tissues cultured in vitro frequently lack such functional vasculature, and thus result in a necrotic core of the cell aggregate. To extend the culture period of the three-dimensional tissue, perfusable vasculature is crucial. It will contribute not only to the long-term culture for regenerative applications of tissues but also to deepen our understanding of organ morphogenesis.

In this presentation, I will explain a method to use angiogenic sprouts to connect the inside of a tissue model, spheroid or organoid, with microfluidic channels via vessel. Three types of tissue models were used: co-cultured spheroids of hLFs and HUVECs, and tri-cultured spheroids of hLFs, HUVECs, and tumor cells, and kidney organoids. This enables us to perfuse the inside of spheroids to deliver oxygen and nutrients. Moreover, some preliminary evaluation of tumor growth and drug evaluation will be presented.

We have extended the on-chip vascular formation method to a three-dimensional spheroid containing tumor cells and kidney organoids. Although we successfully optimized conditions to induce sprouting toward the co-cultured spheroid and found the lumen formation, it was not readily applicable to other cell types. Therefore, we took advantage of the angiogenic factors from hLFs even in the tumor spheroid model for vascularization. Future work includes many applications such as a high-throughput assay for drug screening and a long-term culture of organoids for studying organogenesis. The model provides a new assay platform for the tissue-culture with vasculatures at in vivo-like high cell density.