Transparent, Compliant 3D Mesostructures for Precise Evaluation of Mechanical Characteristics of Organoids

Recently developed methods for transforming two-dimensional (2D) patterns of thin film materials into 3D mesostructures create many interesting opportunities in microsystems design. A growing area of interest is in multifunctional thermal, electrical, chemical and optical interfaces to biological tissues, particularly 3D multicellular, millimeter-scale constructs such as spheroids, assembloids and organoids. This paper presents examples of 3D mechanical interfaces, in which thin ribbons of parylene-C form the basis of transparent, highly compliant frameworks that can be reversibly opened and closed to capture, envelop and mechanically restrain fragile 3D tissues in a gentle, non-destructive manner, for precise measurements of viscoelastic properties using techniques in nanoindentation. Finite element analysis serves as a design tool to guide selection of geometries and material parameters for shape-matching 3D architectures tailored to organoids of interest. These computational approaches also quantitate all aspects of deformations during the processes of opening and closing the structures and of forces imparted by them onto the surfaces of enclosed soft tissues. Studies by nanoindentation show effective Young’s moduli in the range from 1.5 to 2.5 kPa depending on the age of the organoid. This collection of results suggest broad utility in non-invasive mechanical measurements of millimeter-scale, soft biological tissues