Many studies suggest that external forces applied to cells generate signals that are as potent as those of biochemical stimuli. To understand how these forces are transmitted to the molecular structures of cells, and how they might be transduced into biochemical reactions, require measuring both cell mechanical properties (CMPs) and biological pathways in a physiological environment. For this purpose, we will present measurements, through rheological approaches, of CMPs in a label-free manner performed thanks to an automated imaging system devoted to live cells combining digital holographic microscopy, environmental control, and microfluidic assays.
Recently, interest in the biophysics of cells has been stimulated by evidence from many studies that external force applied to a cell generates signals that are as potent as those of biochemical stimuli for cell growth, differentiation, migration and function. Furthermore, living cells as open systems maintain their homeostasis, i.e. the internal condition necessary for physiological functioning, by exchanging substances with their environments including energy substrate, ions and water across their membrane. Consequently, the objective is to develop milli/microfluidic assays to measure biophysical properties of human cells with a multi-modality imaging system combining digital holographic microscopy and fluorescence microscopy.
The recent developments in stem cell biology especially the generation of induced pluripotent stem cells (iPSCs) has made possible the development of in vitro cellular models of developmental brain disorders including schizophrenia. Within this framework, we will present how quantitative phase imaging and in particular quantitative phase digital holographic microscopy (QP-DHM), as a label-free technique is able to study these in vitro cellular models and identify both some pathophysiological processes and cell biomarkers related to developmental brain disorders. This will be illustrated by the exploration with QP-DHM of human neuronal networks derived from iPSCs coming from patients suffering from schizophrenia.