Mechanically adaptive electronic skins (e-skins) emulate tactition and thermoception by cutaneous mechanoreceptors and thermoreceptors in human skin, respectively. When exposed to multiple stimuli including mechanical and thermal stimuli, discerning and quantifying precise sensing signals from sensors embedded in e-skins are critical. In addition, different detection modes for mechanical stimuli, rapidly adapting (RA) and slowly adapting (SA) mechanoreceptors in human skin are simultaneously required. Herein, we demonstrate the fabrication of a highly sensitive, pressure-responsive organic field-effect transistor (OFET) array enabling both RA- and SA- mode detection by adopting easily deformable, mechano-electrically coupled, microstructured ferroelectric gate dielectrics and an organic semiconductor channel. We also demonstrate that the OFET array can separate out thermal stimuli for thermoreception during quantification of SA-type static pressure, by decoupling the input signals of pressure and temperature. Specifically, we adopt piezoelectric-pyroelectric coupling of highly crystalline, microstructured poly(vinylidene fluoride-trifluoroethylene) gate dielectric in OFETs with stimuli to allow monitoring of RA- and SA-mode responses to dynamic and static forcing conditions, respectively. This approach enables us to apply the sensor array to e-skins for bio-monitoring of humans and robotics.
This study identified the cytotoxic mechanisms of aminoamide local anesthetics acting on rotator cuff tenofibroblasts. The greatest margin of safety was found in lower anesthetic concentrations in general and more specifically in the use of ropivacaine.
The stiffness of hydrogels has been reported to direct cell fate. Here, we found that the stiffness of hydrogels promotes the reprogramming of mouse embryonic fibroblasts into induced pluripotent stem cells (iPSCs). We prepared cell culture substrates of various stiffnesses (0.1, 1, 4, 10, and 20 kPa) using a polyacrylamide hydrogel. We found that culture on a soft hydrogel plays an important role in inducing cellular reprogramming into iPSCs via activation of mesenchymal-to-epithelial transition and enhancement of stemness marker expression. These results suggest that physical signals at the interface between cell and substrate can be used as a potent regulator to promote cell fate changes associated with reprogramming into iPSCs, which may lead to effective and reproducible iPSC-production.
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