SummaryCell membrane is the first medium from where a cell senses and responds to external stress stimuli. Exploring the tension changes in cell membrane will help us to understand intracellular force transmission. Here, a biosensor (named MSS) based on fluorescence resonance energy transfer is developed to visualize cell membrane tension. Validity of the biosensor is first verified for the detection of cell membrane tension. Results show a shear stress-induced heterogeneous distribution of membrane tension with the biosensor, which is strengthened by the disruption of microfilaments or enhancement of membrane fluidity, but weakened by the reduction of membrane fluidity or disruption of microtubules. These findings suggest that the MSS biosensor is a beneficial tool to visualize the changes and distribution of cell membrane tension. Besides, cell membrane tension does not display obvious polar distribution, indicating that cellular polarity changes do not first occur on the cell membrane during mechanical transmission.
Intracellular calcium dynamics plays an important role in the regulation of vascular endothelial cellular functions. In order to probe the intracellular calcium dynamic response under synergistic effect of wall shear stress (WSS) and adenosine triphosphate (ATP) signals, a novel microfluidic device, which provides the adherent vascular endothelial cells (VECs) on the bottom of microchannel with WSS signal alone, ATP signal alone, and different combinations of WSS and ATP signals, is proposed based upon the principles of fluid mechanics and mass transfer. The spatiotemporal profiles of extracellular ATP signals from numerical simulation and experiment studies validate the implementation of our design. The intracellular calcium dynamics of VECs in response to either WSS signal or ATP signal alone, and different combinations of WSS and ATP signals have been investigated. It is found that the synergistic effect of the WSS and ATP signals plays a more significant role in the signal transduction of VECs rather than that from either WSS signal or ATP signal alone. In particular, under the combined stimuli of WSS and ATP signals with different amplitudes and frequencies, the amplitudes and frequencies of the intracellular Ca dynamic signals are observed to be closely related to the amplitudes and frequencies of WSS or ATP signals.
The leaf venation is considered to be an optimal transportation system with the mesophyll cells being divided by minor veins into small regions named areoles. The transpiration of water in different regions of a leaf fluctuates over time making the transportation of water in veins fluctuate as well. However, because of the existence of multiple paths provided by the leaf venation network and the pits on the walls of the vessels, the pressure field and nutrient concentration in the areoles that the mesophyll cells live in are almost uniform. Therefore, inspired by such structures, a microfluidic design of a novel cell culture chamber has been proposed to obtain a stable and uniform microenvironment. The device consists of a novel microchannel system imitating the vessels in the leaf venation to transport the culture medium, a cell culture chamber imitating the areole and microgaps imitating the pits. The effects of the areole and pit on flow fields in the cell culture chamber have been discussed. The results indicate that the bio-inspired microfluidic device is a robust platform to provide an in vivo like fluidic microenvironment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.