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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3

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Now showing 1 - 7 of 7
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    Pangolin-inspired untethered magnetic robot for on-demand biomedical heating applications
    (Nature Portfolio, 2023) Soon, Ren Hao; Yin, Zhen; Dogan, Metin Alp; Dogan, Nihal Olcay; Tiryaki, Mehmet Efe; Karacakol, Alp Can; Aydin, Asli; Esmaeili-Dokht, Pouria; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Untethered magnetic miniature soft robots capable of accessing hard-to-reach regions can enable safe, disruptive, and minimally invasive medical procedures. However, the soft body limits the integration of non-magnetic external stimuli sources on the robot, thereby restricting the functionalities of such robots. One such functionality is localised heat generation, which requires solid metallic materials for increased efficiency. Yet, using these materials compromises the compliance and safety of using soft robots. To overcome these competing requirements, we propose a pangolin-inspired bi-layered soft robot design. We show that the reported design achieves heating > 70 degrees C at large distances > 5cm within a short period of time <30s, allowing users to realise on-demand localised heating in tandem with shape-morphing capabilities. We demonstrate advanced robotic functionalities, such as selective cargo release, in situ demagnetisation, hyperthermia and mitigation of bleeding, on tissue phantoms and ex vivo tissues. Untethered soft robots developed to date display limited functionalities beyond locomotion and cargo delivery. Here, the authors present a pangolin-inspired robotic design which enables heating >70 degrees C at distances > 5cm without compromising their compliance, for biomedical applications.
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    Programmable mechanical devices through magnetically tunable bistable elements
    (National Academy of Sciences, 2023) Pal, Aniket; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Mechanical instabilities, especially in the form of bistable and multistable mechanisms, have recently garnered a lot of interest as a mode of improving the capabilities and increasing the functionalities of soft robots, structures, and soft mechanical systems in general. Although bistable mechanisms have shown high tunability through the variation of their material and design variables, they lack the option of modifying their attributes dynamically during operation. Here, we propose a facile approach to overcome this limitation by dispersing magnetically active microparticles throughout the structure of bistable elements and using an external magnetic field to tune their responses. We experimentally demonstrate and numerically verify the predictable and deterministic control of the response of different types of bistable elements under varying magnetic fields. Additionally, we show how this approach can be used to induce bistability in intrinsically monostable structures simply by placing them in a controlled magnetic field. Furthermore, we show the application of this strategy in precisely controlling the features (e.g., velocity and direction) of transition waves propagating in a multista-ble lattice created by cascading a chain of individual bistable elements. Moreover, we can implement active elements like a transistor (gate controlled by magnetic fields) or magnetically reconfigurable functional elements like binary logic gates for processing mechanical signals. This strategy serves to provide programming and tuning capabilities required to allow more extensive utilization of mechanical instabilities in soft systems with potential functions such as soft robotic locomotion, sensing and triggering ele-ments, mechanical computation, and reconfigurable devices.
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    Actuation-enhanced multifunctional sensing and information recognition by magnetic artificial cilia arrays
    (National Academy of Sciences, 2023) Han, Jie; Dong, Xiaoguan; Yin, Zhen; Zhang, Shuaizhong; Li, Meng; Zheng, Zhiqiang; Ugurlu, Musab Cagri; Jiang, Weitao; Liu, Hongzhong; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Artificial cilia integrating both actuation and sensing functions allow simultaneously sensing environmental properties and manipulating fluids in situ, which are promising for environment monitoring and fluidic applications. However, existing artificial cilia have limited ability to sense environmental cues in fluid flows that have versatile information encoded. This limits their potential to work in complex and dynamic fluid-filled environments. Here, we propose a generic actuation- enhanced sensing mechanism to sense complex environmental cues through the active interaction between artificial cilia and the surrounding fluidic environments. The proposed mechanism is based on fluid-cilia interaction by integrating soft robotic artificial cilia with flexible sen-sors. With a machine learning-based approach, complex environmental cues such as liquid viscosity, environment boundaries, and distributed fluid flows of a wide range of velocities can be sensed, which is beyond the capability of existing artificial cilia. As a proof of concept, we implement this mechanism on magnetically actuated cilia with integrated laser- induced graphene-based sensors and demonstrate sensing fluid apparent viscosity, environment boundaries, and fluid flow speed with a reconfigur-able sensitivity and range. The same principle could be potentially applied to other soft robotic systems integrating other actuation and sensing modalities for diverse environmental and fluidic applications.
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    Magnetically assisted soft milli-tools for occluded lumen morphology detection
    (Amer Assoc Advancement Science, 2023) Yan, Yingbo; Wang, Tianlu; Zhang, Rongjing; Liu, Yilun; Hu, Wenqi; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Methodologies based on intravascular imaging have revolutionized the diagnosis and treatment of endovascular diseases. However, current methods are limited in detecting, i.e., visualizing and crossing, complicated occluded vessels. Therefore, we propose a miniature soft tool comprising a magnet-assisted active deformation segment (ADS) and a fluid drag-driven segment (FDS) to visualize and cross the occlusions with various morphologies. First, via soft-bodied deformation and interaction, the ADS could visualize the structure details of partial occlusions with features as small as 0.5 millimeters. Then, by leveraging the fluidic drag from the pulsatile flow, the FDS could automatically detect an entry point selectively from severe occlusions with complicated microchannels whose diameters are down to 0.2 millimeters. The functions have been validated in both biologically relevant phantoms and organs ex vivo. This soft tool could help enhance the efficacy of minimally invasive medicine for the diagnosis and treatment of occlusions in various circulatory systems.
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    In situ sensing physiological properties of biological tissues using wireless miniature soft robots
    (Amer Assoc Advancement Science, 2023) Wang, Chunxiang; Wu, Yingdan; Dong, Xiaoguang; Armacki, Milena; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Implanted electronic sensors, compared with conventional medical imaging, allow monitoring of advanced physiological properties of soft biological tissues continuously, such as adhesion, pH, viscoelasticity, and biomarkers for disease diagnosis. However, they are typically invasive, requiring being deployed by surgery, and frequently cause inflammation. Here we propose a minimally invasive method of using wireless miniature soft robots to in situ sense the physiological properties of tissues. By controlling robot-tissue interaction using external magnetic fields, visualized by medical imaging, we can recover tissue properties precisely from the robot shape and magnetic fields. We demonstrate that the robot can traverse tissues with multimodal locomotion and sense the adhesion, pH, and viscoelasticity on porcine and mice gastrointestinal tissues ex vivo, tracked by x-ray or ultrasound imaging. With the unprecedented capability of sensing tissue physiological properties with minimal invasion and high resolution deep inside our body, this technology can potentially enable critical applications in both basic research and clinical practice.
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    A versatile jellyfish-like robotic platform for effective underwater propulsion and manipulation
    (Amer Assoc Advancement Science, 2023) Wang, Tianlu; Joo, Hyeong-Joon; Song, Shanyuan; Hu, Wenqi; Keplinger, Christoph; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Underwater devices are critical for environmental applications. However, existing prototypes typically use bulky, noisy actuators and limited configurations. Consequently, they struggle to ensure noise-free and gentle inter-actions with underwater species when realizing practical functions. Therefore, we developed a jellyfish-like robotic platform enabled by a synergy of electrohydraulic actuators and a hybrid structure of rigid and soft components. Our 16-cm-diameter noise-free prototype could control the fluid flow to propel while manipulat-ing objects to be kept beneath its body without physical contact, thereby enabling safer interactions. Its against -gravity speed was up to 6.1 cm/s, substantially quicker than other examples in literature, while only requiring a low input power of around 100 mW. Moreover, using the platform, we demonstrated contact-based object ma-nipulation, fluidic mixing, shape adaptation, steering, wireless swimming, and cooperation of two to three robots. This study introduces a versatile jellyfish-like robotic platform with a wide range of functions for diverse applications.
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    3D-printed micrometer-scale wireless magnetic cilia with metachronal programmability
    (Amer Assoc Advancement Science, 2023) Zhang, Shuaizhong; Hu, Xinghao; Li, Meng; Bozuyuk, Ugur; Zhang, Rongjing; Suadiye, Eylul; Han, Jie; Wang, Fan; Onck, Patrick; Department of Mechanical Engineering; Department of Mechanical Engineering; Sitti, Metin; College of Engineering; School of Medicine
    Biological cilia play essential roles in self-propulsion, food capture, and cell transportation by performing coor-dinated metachronal motions. Experimental studies to emulate the biological cilia metachronal coordination are challenging at the micrometer length scale because of current limitations in fabrication methods and ma-terials. We report on the creation of wirelessly actuated magnetic artificial cilia with biocompatibility and meta-chronal programmability at the micrometer length scale. Each cilium is fabricated by direct laser printing a silk fibroin hydrogel beam affixed to a hard magnetic FePt Janus microparticle. The 3D-printed cilia show stable actuation performance, high temperature resistance, and high mechanical endurance. Programmable meta-chronal coordination can be achieved by programming the orientation of the identically magnetized FePt Janus microparticles, which enables the generation of versatile microfluidic patterns. Our platform offers an unprecedented solution to create bioinspired microcilia for programmable microfluidic systems, biomedical en-gineering, and biocompatible implants.