P022 - Zipper-stiffness mechanism of chondrospheres tissue fusion
Abstract
Purpose
Tissue fusion is a naturally occurred ubiquitous phenomenon in embryonic development. To date, tissue spheroids biofabricated from human chondrocytes, or so-called chondrospheres, have been successfully used for cartilage repair company Co.don. Tissue spheroids are used as self-assembling building blocks in 3D bioprinting technology due to the phenomenon of tissue spheroids fusion as a fundamental biological principle of new emerging organ. However, the exact mechanism of tissue spheroids fusion remains elusive. The aim of this study was the experimental testing of new original «zipper-stiffness hypothesis» of tissue spheroids fusion, which implies that just two basic processes: cell adhesion and tissue spheroids stiffness drive and control the tissue fusion process.
Methods and Materials
Tissue spheroids have been chosen as a model object for the experiment. Chondrospheres were biofabricated from primary culture of sheep chondrocytes using Corning Spheroid Microplates (Corning, USA). Biomechanical properties of tissue spheroids have been measured using commercial tensiometer «Microsquisher» according to the manufacturer’s protocol (CellScale, Canada). Residual stress was estimated by measuring open angle which was formed after microsurgical cutting of tissue spheroids according to previously described protocol. All quantitative data have been systematically analyzed. The tissue spheroids fusion kinetics has been estimated using so-called «doublets» or pairs of adjacent tissue spheroids as it has been decsribed in detailes previously.
Results
Our experimental data demonstrate that doublets of tissue spheroids with released from residual stress using micro dissection cutting fuse faster than doublets of control intact tissue spheroids. The proposed «zipper-stiffness hypothesis» of mechanism of issue spheroid fusion has been experimentally validated.
Conclusion
For the first time, we report herein the experimental validation of this novel «zipper-stiffness hypothesis» using tensiometry and residual stress assessment and tissue spheroids fusion kinetics.
