Investigation of hypoxia-induced myocardial injury dynamics in a tissue interface mimicking microfluidic device.

Myocardial infarction is a major cause of morbidity and mortality worldwide. However, the methodological development of a spatiotemporally controllable investigation of the damage events in myocardial infarction remains challengeable. In the present study, we describe a micropillar array-aided tissue interface mimicking microfluidic device for the dynamic study of hypoxia-induced myocardial injury in a microenvironment-controllable manner. The mass distribution in the device was visually characterized, calculated, and systematically evaluated using the micropillar-assisted biomimetic interface, physiologically relevant flows, and multitype transportation. The fluidic microenvironment in the specifically functional chamber for cell positioning and analysis was successfully constructed with high fluidic relevance to the myocardial tissue. We also performed a microenvironment-controlled microfluidic cultivation of myocardial cells with high viability and regular structure integration. Using the well-established culture device with a tissue-mimicking microenvironment, a further on-chip investigation of hypoxia-induced myocardial injury was carried out and the varying apoptotic responses of myocardial cells were temporally monitored and measured. The results show that the hypoxia directionally resulted in observable cell shrinkage, disintegration of the cytoskeleton, loss of mitochondrial membrane potential, and obvious activation of caspase-3, which indicates its significant apoptosis effect on myocardial cells. We believe this microfluidic device can be suitable for temporal investigations of cell activities and responses in myocardial infarction. It is also potentially valuable to the microcontrol development of tissue-simulated studies of multiple clinical organ/tissue disease dynamics.