Human body IoT systems based on the triboelectrification effect for energy harvesting, sensing, and interaction via wireless communication.

Origami has been proved as a valuable tool to develop deployable, multifunctional, and tunable devices for diverse engineering applications. Inspired by the Kresling origami, this article presents a soft pneumatic actuator with vacuum control to realize the compound motion of twist and contraction. The twist direction varies as the crease angle changes and it offers pure contraction after combining two actuators with reverse creases. Our actuator can lift 180 folds of its weight and achieve the contraction ratio of 47%, while the response time is below 0.3 s. The origami-based actuator can realize an adjustable bistable property, leading to the possibility for external stimulus detection and mechanical memory devices, where the sensitivity can be regulated by the initial vacuum pressure. Through several actuators, we demonstrate the reconfigurable crawling robots capable of worm-like creep, alternating-step locomotion as well as obstacle detection. After activating all the actuators, the four-actuator robot with two working modes is validated to perform agilely for confined space navigation, showing our actuator has the potential in soft robotics applications.

Highly flexible and environmentally adaptive soft robots have received considerable attention. There remains a demand for soft robots to realize the stiffness modulation and variable workspace for robust and versatile manipulations. This article presents a compact soft gripper with a polylactic acid-based variable stiffness module (VSM) and a rigid retractable mechanism to achieve soft-rigid hybrid actuation. The soft gripper can enhance its stiffness by 18-fold without sacrificing flexibility due to the VSM. A heating circuit is designed to divide the VSM into three regions. Each region can be activated separately for varying flexible segments to amplify the dexterity. Meanwhile, the water-cooling system accelerates the heat exchange, thus reducing the cooling time from ∼400 to 39 s. The rigid retractable mechanism can adjust the initial layout of the gripper to expand the workspace and perform manipulation by opening and closing fingers. The soft finger combined with stiffness tunability can maintain its deformation after being stiffened to realize morphing. Therefore, it can efficiently perform a grasp with a high load and avoid repeated heating and cooling, especially for items with a similar shape. The performance of the gripper is further validated by measuring the grasping force and grasping demonstration with various objects, showing its robustness and dexterity in versatile tasks.

Using external actuation sources to navigate untethered drug-eluting microrobots in the bloodstream offers great promise in improving the selectivity of drug delivery, especially in oncology, but the current field forces are difficult to maintain with enough strength inside the human body (>70-centimeter-diameter range) to achieve this operation. Here, we present an algorithm to predict the optimal patient position with respect to gravity during endovascular microrobot navigation. Magnetic resonance navigation, using magnetic field gradients in clinical magnetic resonance imaging (MRI), is combined with the algorithm to improve the targeting efficiency of magnetic microrobots (MMRs). Using a dedicated microparticle injector, a high-precision MRI-compatible balloon inflation system, and a clinical MRI, MMRs were successfully steered into targeted lobes via the hepatic arteries of living pigs. The distribution ratio of the microrobots (roughly 2000 MMRs per pig) in the right liver lobe increased from 47.7 to 86.4% and increased in the left lobe from 52.2 to 84.1%. After passing through multiple vascular bifurcations, the number of MMRs reaching four different target liver lobes had a 1.7- to 2.6-fold increase in the navigation groups compared with the control group. Performing simulations on 19 patients with hepatocellular carcinoma (HCC) demonstrated that the proposed technique can meet the need for hepatic embolization in patients with HCC. Our technology offers selectable direction for actuator-based navigation of microrobots at the human scale.