Soft Electrochemical Actuators with a Two-Dimensional Conductive Metal-Organic Framework Nanowire Array.

Electrically activated soft actuators capable of large deformation are powerful and broadly applicable in multiple fields. However, designing soft actuators that can withstand a high strain, provide a large actuation displacement, and exhibit stable reversibility are still the main challenges toward their practical application. Here, for the first time, we report a two-dimensional (2D) conductive metal-organic framework (MOF) based electrochemical actuator, which consists of vertically oriented and hierarchical Ni-CAT NWAs/CNF electrodes through the use of a facile one-step in situ hydrothermal growth method. The soft actuator prepared in this study demonstrated improvements in actuation performance and benefits from both the intrinsically ordered porous architecture and efficient transfer pathways for fast ion and electron transport; furthermore, this actuator facilitated a considerably high diffusion rate and low interfacial resistance. In particular, the actuator demonstrated a rapid response (<19 s) at a 3 V DC input, large actuation displacement (12.1 mm), and a correspondingly high strain of 0.36% under a square-wave AC voltage of ±3 V. Specifically, the actuator achieved a broad-band frequency response (0.1-20 Hz) and long-term cyclability in air (10000 cycles) with a negligible degradation in actuation performance. Our work demonstrates new opportunities for bioinspired artificial actuators and overcomes current limitations in electrode materials for soft robotics and bionics.

[Effects of L-arginine on the microcirculation of rat island skin flaps after ischemia- reperfusion].

OBJECTIVE: To investigate the effects of L-arginine on the microcirculation and survival of rat island skin flaps after ischemia-reperfusion. METHOD: A right lower abdominal island flap was created in SD rats and the microcirculatory blood flow in these flaps measured with laser Doppler velocimetry following L-arginine injection via the contralateral femoral artery. Both NO and malondialdehyde (MDA) levels in the flaps were assayed and the survival of the flaps replanted in situ was evaluated 1 week later. RESULTS: L-arginine treatment caused increase in the microcirculatory blood flow of the flaps and elevation of NO while and decrease of MDA levels. The survival rate of the flaps with L-arginine treatment was significantly higher than the flaps from saline-treated and normal rats. CONCLUSION: L-arginine can improve the survival of island flap through increasing the microcirculatory blood flow and lessening ischemia-reperfusion injury of the flaps.