In vitro cell stretching devices and their applications:From cardiomyogenic differentiation to tissue engineering

Mechanical stretch plays an important role in the control of cardiomyocyte behavior,as well as in the study of the mechanisms of cardiovascular function and pathology.The complexity involved in biological systems in vivo has created a need for better in vitro techniques,thus a variety of cell stretching devices have been developed for a deeper understanding of cellular responses to strain.In this review,we introduce the design,functionality,and characteristics of multiple types of cell stretching devices from two and three dimensions,then discuss the research progress of promoting cardiomyogenic differentiation of stem cells by external stretching and its application in cardiac tissue engineering.

In vitro fluidic systems: Applying shear stress on endothelial cells

Endothelial cells(ECs)that reside on the surface of blood vessels are constantly exposed to mechanical stimulation,including shear stress.Fluid shear stress(FSS)controls multiple physiological processes in ECs,regulating various pathways that maintain vascular tone and homeostasis function.The complexity of in vivo biological systems raises a demand for better in vitro techniques,which can generate FSS to closely mimic the cellular microenvironment.Through the rational design and use of flow chamber devices,in vitro fluidic systems are critical for a deeper understanding of endothelial responses to various shear conditions.The paper describes principal types of FSS systems,including functional attributes,development process and recent experiments on ECs.Finally,we prospect their possible contribution in the field of endothelial diseases.

Organic photovoltaic device enhances the neural differentiation of rat bone marrow-derived mesenchymal stem cells

Electrical stimulation is known to be involved in stem cell differentiation,particularly neural differentiation.Various electrical stimulation systems and devices have been developed for neural tissue engineering.The organic photovoltaic materials PM6 and Y6 have showed high-power conversion efficiency.In this study,we used PM6 and Y6 to develop an organic photovoltaic device(OPD)to supply electrical stimulation.The photoelectric stimulation by the OPD showed no impact on cell viability.We tested the neural differentiation potential of rat bone marrow-derived mesenchymal stem cells(rBMSCs)under light induced electrical stimulation.The changes in cell morphology suggested that photoelectric stimulation significantly increased the neurite length and the number of extremities of differentiated neural cells.In addition,genes of neuron markers and neurotrophic factors were upregulated when rBMSCs were under photoelectric stimulation.Furthermore,the calcium influx of differentiated cells responding to acetylcholine and the phosphorylation of extracellular-signal-regulated kinase(ERK)1 and 2,protein kinase B(AKT)and mammalian target of rapamycin(mTOR)were significantly elevated after photoelectric stimulation.These findings demonstrated that PM6:Y6 based OPD could provide photoelectric stimulation to enhance rBMSCs neural differentiation,which might be an alternative approach to electrically manipulate stem cells differentiation into neural cells in vitro.