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Abstract The epithelial microenvironment is incredibly dynamic, subjected to mechanical cues including cyclic stretch. While cyclic cell stretching platforms have revealed epithelial cell reorientation and gap formation, few studies have investigated the long-term effects of cyclic stretch on cell migration. We measured the migratory response of the epithelium to a range of physiologically relevant frequencies and stretch. Our results indicate that lower stretch frequencies (i.e., 0.1 Hz) suppress epithelial migration, accompanied by cell reorientation and high cell shape solidity. We found that this response is also accompanied by increased recruitment of vinculin to cell-cell contacts, and this recruitment is necessary to suppress cell movements. These results confirm the mechanosensitive nature of vinculin within the adherens junction, but independently reveal a novel mechanism of low frequency stress response in supporting epithelial integrity by suppressing cell migration. 

Tactile sensing is essential for robots to perceive and react to the environment. However, it remains a challenge to make large-scale and flexible tactile skins on robots. Industrial machine knitting provides solutions to manufacture customiz-able fabrics. Along with functional yarns, it can produce highly customizable circuits that can be made into tactile skins for robots. In this work, we present RobotSweater, a machine-knitted pressure-sensitive tactile skin that can be easily applied on robots. We design and fabricate a parameterized multi-layer tactile skin using off-the-shelf yarns, and characterize our sensor on both a flat testbed and a curved surface to show its robust contact detection, multi-contact localization, and pressure sensing capabilities. The sensor is fabricated using a well-established textile manufacturing process with a programmable industrial knitting machine, which makes it highly customizable and low-cost. The textile nature of the sensor also makes it easily fit curved surfaces of different robots and have a friendly appearance. Using our tactile skins, we conduct closed-loop control with tactile feedback for two applications: (1) human lead-through control of a robot arm, and (2) human-robot interaction with a mobile robot.