Strain sensors with high sensitivity, broad sensing ranges and excellent durable stability are highly desirable due to their promising potential in electronic skins and human-friendly wearable interactive systems. Herein, we report a high-performance strain sensor based on rGO (reduced graphene oxide)/DI (deionized water) sensing elements. The strain sensors were fabricated by using Ecoflex rubber filled with rGO/DI conductive liquids via template methods, making the process simple, low-cost and scalable. The as-assembled strain sensors can be used to reflect both stretching and compressing with high sensitivity (a maximum gauge factor of 31.6 and a pressure sensitivity of 0.122 kPa), an ultralow limit of detection (0.1% strain), and excellent reliability and stability (>15 000 cycles for pressuring and >10 000 cycles for stretching). In particular, the maximum sensing range is up to 400%, much wider than that of the sensor recently reported. More significantly, the strain sensors are able to distinguish between touch/compressive (resistance decrease) and tensile (resistance increase) deformation, which has not been explored before. This interesting property of strain sensors is due to the micro-contact of nanomaterials in a liquid environment. The sensing liquid of the device can be refilled when it fails, and this enables the recycling of the materials and reduces the waste rate. Therefore, it is attractive and promising for practical applications in multifunctional wearable electronics such as the detection of acoustic vibration, human vocalization and other human motions.

Paper-based (PB) green electronics is an emerging and potentially game-changing technology due to ease of recycling/disposal, the economics of manufacture and the applicability to flexible electronics. Herein, new-type printable PB strain sensors (PPBSSs) from graphite glue (graphite powder and methylcellulose) have been fabricated. The graphite glue is exposed to thermal annealing to produce surface micro/nano cracks, which are very sensitive to compressive or tensile strain. The devices exhibit a gauge factor of 804.9, response time of 19.6 ms and strain resolution of 0.038%, all performance indicators attaining and even surpassing most of the recently reported strain sensors. Due to the distinctive sensing properties, flexibility and robustness, the PPBSSs are suitable for monitoring of diverse conditions such as structural strain, vibrational motion, human muscular movements and visual control.

Remote ischaemic preconditioning (RIPC) is well known to protect the myocardium against ischaemia/reperfusion injury (IRI). Exosomes are small extracellular vesicles that have become the key mediators of intercellular communication. Various studies have confirmed that circulating exosomes mediate RIPC. However, the underlying mechanisms for RIPC-induced exosome-mediated cardioprotection remain elusive. In our study, we found that the expression level of miR-24 was higher in exosomes derived from the plasma of rats subjected to RIPC than in exosomes derived from the plasma of control rats in vivo. The rat plasma exosomes could be taken up by H9c2 cells. In addition, miR-24 was present in RIPC-induced exosomes and played a role in reducing oxidative stress-mediated injury and decreasing apoptosis by downregulating Bim expression in H2O2-treated H9c2 cells in vitro. In vivo, miR-24 in RIPC-induced exosomes reduced cardiomyocyte apoptosis, attenuated the infarct size and improved heart function. Furthermore, the apoptosis-reducing effect of miR-24 was counteracted by miR-24 antagomirs or inhibitors both in vitro and in vivo. Therefore, we provided evidence that RIPC-induced exosomes could reduce apoptosis by transferring miR-24 in a paracrine manner and that miR-24 in the exosomes plays a central role in mediating the protective effects of RIPC.

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Here surface potential of chemical vapor deposition (CVD) grown 2D MoS with various layers is reported, and the effect of adherent substrate and light illumination on surface potential of monolayer MoS are investigated. The surface potential of MoS on Si/SiO substrate decreases from 4.93 to 4.84 eV with the increase in the number of layer from 1 to 4 or more. Especially, the surface potentials of monolayer MoS are strongly dependent on its adherent substrate, which are determined to be 4.55, 4.88, 4.93, 5.10, and 5.50 eV on Ag, graphene, Si/SiO , Au, and Pt substrates, respectively. Light irradiation is introduced to tuning the surface potential of monolayer MoS , with the increase in light intensity, the surface potential of MoS on Si/SiO substrate decreases from 4.93 to 4.74 eV, while increases from 5.50 to 5.56 eV on Pt substrate. The I-V curves on vertical of monolayer MoS /Pt heterojunction show the decrease in current with the increase of light intensity, and Schottky barrier height at MoS /Pt junctions increases from 0.302 to 0.342 eV. The changed surface potential can be explained by trapped charges on surface, photoinduced carriers, charge transfer, and local electric field.