Cell-stretching devices: advances and challenges in biomedical research and live-cell imaging.

Mechanical stretching is experienced ubiquitously by human tissues and their constituent cells and impacts biochemical and (mechano)biological processes relevant to health and disease. Numerous cell-stretching devices (CSDs) have been developed and used to apply mechanical strain to cells and tissues in in vitro settings, however, few have shown compatibility with live-cell microscopy. In most microscopy-compatible CSDs, imaging is performed post-mechanical stretching while live-cell imaging during cyclic stretching is very rarely shown, especially at high stretching frequencies and for long experiments (i.e., hours long). Live-cell imaging during cell stretching has revealed distinct time-dependent biomechanical features of cells, such as cell fluidization at high amplitudes or frequencies, or cracking followed by recovery of cell monolayers. Basic human functions such as breathing and digestion require mechanical stretching of cells and tissues. However, when it comes to laboratory experiments, the mechanical stretching that cells experience in the body is not often replicated, limiting the biomimetic nature of the studies and the relevance of results. Herein, we establish the importance of mechanical stretching during in vitro investigations by reviewing seminal works performed using cell-stretching platforms, highlighting important outcomes of these works as well as the engineering characteristics of the platforms used. Emphasis is placed on the compatibility of cell-stretching devices (CSDs) with live-cell imaging as well as their limitations and on the research advancements that could arise from live-cell imaging performed during cell stretching. [ABSTRACT FROM AUTHOR]