lixinxin

Humans possess manual dexterity, motor skills, and other physical abilities that rely on feedback provided by the somatosensory system. Herein, a method is reported for creating soft somatosensitive actuators (SSAs) via embedded 3D printing, which are innervated with multiple conductive features that simultaneously enable haptic, proprioceptive, and thermoceptive sensing. This novel manufacturing approach enables the seamless integration of multiple ionically conductive and fluidic features within elastomeric matrices to produce SSAs with the desired bioinspired sensing and actuation capabilities. Each printed sensor is composed of an ionically conductive gel that exhibits both long-term stability and hysteresis-free performance. As an exemplar, multiple SSAs are combined into a soft robotic gripper that provides proprioceptive and haptic feedback via embedded curvature, inflation, and contact sensors, including deep and fine touch contact sensors. The multimaterial manufacturing platform enables complex sensing motifs to be easily integrated into soft actuating systems, which is a necessary step toward closed-loop feedback control of soft robots, machines, and haptic devices.

Soft somatosensitive actuators are created by embedded 3D printing of ionically conductive and fluidic features within molded elastomeric matrices. Specifically, these actuators are innervated with sensors that bestow soft robotic grippers with proprioceptive, haptic, and thermoceptive sensing capabilities akin to our own bodies'. This approach represents a foundational advance with potential applications in soft robotic, wearable, and haptic devices.

Most electrocatalysts for the ethanol oxidation reaction suffer from extremely limited operational durability and poor selectivity toward the CC bond cleavage. In spite of tremendous efforts over the past several decades, little progress has been made in this regard. This study reports the remarkable promoting effect of Ni(OH)₂ on Pd nanocrystals for electrocatalytic ethanol oxidation reaction in alkaline solution. A hybrid electrocatalyst consisting of intimately mixed nanosized Pd particles, defective Ni(OH)₂ nanoflakes, and a graphene support is prepared via a two-step solution method. The optimal product exhibits a high mass-specific peak current of >1500 mA mg⁻¹_Pd, and excellent operational durability forms both cycling and chronoamperometric measurements in alkaline solution. Most impressively, this hybrid catalyst retains a mass-specific current of 440 mA mg⁻¹ even after 20 000 s of chronoamperometric testing, and its original activity can be regenerated via simple cyclic voltammetry cycles in clean KOH. This great catalyst durability is understood based on both CO stripping and in situ attenuated total reflection infrared experiments suggesting that the presence of Ni(OH)₂ alleviates the poisoning of Pd nanocrystals by carbonaceous intermediates. The incorporation of Ni(OH)₂ also markedly shifts the reaction selectivity from the originally predominant C2 pathway toward the more desirable C1 pathway, even at room temperature.

A hybrid electrocatalyst material is reported, which features small Pd nanoparticles abundantly interfaced with Ni(OH)₂ and uniformly supported on graphene nanosheets. The synergy between Pd and Ni(OH)₂ leads to dramatically improved electrocatalytic performance of the precious metal for the ethanol oxidation reaction and markedly shifts its selectivity toward the C1 pathway in alkaline solution.

A fully integrated graphene field-effect transistor (GFET) nanosensor utilizing a novel high-κ solid-gating geometry for a practical biosensor with enhanced sensitivity is presented. Herein, an “in plane” gate supplying electrical field through a 30 nm HfO₂ dielectric layer is employed to eliminate the cumbrous external wire electrode in conventional liquid-gate GFET nanosensors that undesirably limits the device potential in on-site sensing applications. In addition to the advantage in the device integration degree, the transconductance level is found to be increased by about 50% over liquid-gate GFET devices in aqueous-media, thereby improves the sensitivity performance in sensor applications. As the first demonstration of biosensing applications, a small-molecule antibiotic, kanamycin A, is detected by means of an aptameric competitive affinity principle. It is experimentally shown that the label-free and specific quantification of kanamycin A with a concentration resolution at 11.5 × 10⁻⁹ m is achievable through a single direct observation of the 200 s fast bioassay without any further noise canceling. These results demonstrate the utility and practicability of the new devices in label-free biosensing as a novel analytical tool, and potentially hold great promise in other significant biomedical applications.

High-κ solid-gate graphene field-effect transistor (GFET) devices for biosensing applications are developed by employing a planar metallic gate electrode buried by high-κ HfO₂ dielectric layer. These GFET devices eliminate the requirement for an external wire gate electrode that improves the device integration degree, and perform with enhanced sensitivity compared to conventional liquid-gate GFET biosensors.