Advances in experimental approaches for investigating cell aggregate mechanics

Cells tend to form hierarchy structures in native tissues. Formation of cell aggregates in vitro such as cancer spheroids and embryonic bodies provides a unique means to study the mechanical properties and biological behaviors/functions of their counterparts in vivo. In this paper, we review state-of-the-art experimental approaches to assess the mechanical properties and mechanically-induced responses of cell aggregates in vitro. These approaches are classified into five categories according to loading modality, including micropipette aspiration, centrifugation, compression loading, substrate distention, and fluid shear loading. We discussed the advantages and disadvantages of each approach, and the potential biomedical applications. Understanding of the mechanical behavior of cell aggregates provides insights to physical interactions between cells and integrity of biological functions, which may enable mechanical intervention for diseases such as atheromatosis and cancer.