Browsing by Author "Zhu, Zhijie"

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    3D Printed Functional Materials and Devices and Applications in AI-powered 3D Printing on Moving Freeform Surfaces
    (2020-08) Zhu, Zhijie
    The capability of 3D printing a diverse palette of functional inks will enable the mass democratization of manufactured patient-specific wearable devices and smart biomedical implants for applications such as health monitoring and regenerative biomedicines. These personalized wearables could be fabricated via in situ printing --- direct printing of 3D constructs on the target surfaces --- at ease of the conventional fabricate-then-transfer procedure. This new 3D printing technology requires functional (e.g., conductive and viscoelastic) inks and devices (e.g., wearable and implantable sensors) that are compatible with in situ printing, as well as the assistance of artificial intelligence (AI) to sense, adapt, and predict the state of the printing environment, such as a moving hand and a dynamically morphing organ. To advance this in situ printing technology, this thesis work is focused on (1) the development of functional materials and devices for 3D printing, and (2) the AI-assisted 3D printing system. To extend the palette of 3D printable materials and devices, on-skin printable silver conductive inks, hydrogel-based deformable sensors, and transparent electrocorticography sensors were developed. As with the AI for in situ 3D printing, solutions for four types of scenarios were studied (with complexity from low to high): (1) printing on static, planar substrates without AI intervention, with a demonstration of fully printed electrocorticography sensors for implantation in mice; (2) printing on static, non-planar parts with open-loop AI, with a demonstration of printing viscoelastic dampers on hard drives to eliminate specific modes of vibration; (3) printing on moving targets with closed-loop and predictive AI, with demonstrations of printing wearable electronics on a human hand and depositing cell-laden bio-inks on live mice; (4) printing on deformable targets with closed-loop and predictive AI, with demonstrations of printing a hydrogel sensor on a breathing lung and multi-material printing on a phantom face. We anticipate that this convergence of AI, 3D printing, functional materials, and personalized biomedical devices will lead to a compelling future for on-the-scene autonomous medical care and smart manufacturing.
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    Supporting data for "3D Printed Deformable Sensors"
    (2020-04-28) Zhu, Zhijie; Park, Hyun Soo; McAlpine, Michael C; mcalpine@umn.edu; McAlpine, Michael C; McAlpine Research Group
    The data set includes the experimental data and the corresponding code files supporting the results reported in Zhijie Zhu; Hyun Soo Park; Michael C. McAlpine. 3D Printed Deformable Sensors. Sci. Adv., 2020, DOI: 10.1126/sciadv.aba5575. The ability to directly print compliant biomedical devices on live human organs could benefit patient monitoring and wound treatment, which requires the 3D printer to adapt to the various deformations of the biological surface. We developed an in situ 3D printing system that estimates the motion and deformation of the target surface to adapt the toolpath in real time. With this printing system, a hydrogel-based sensor was printed on a porcine lung under respiration-induced deformation. The sensor was compliant to the tissue surface and provided continuous spatial mapping of deformation via electrical impedance tomography. This adaptive 3D printing approach may enhance robot-assisted medical treatments with additive manufacturing capabilities, enabling autonomous and direct printing of wearable electronics and biological materials on and inside the human body.
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    Supporting data for "3D Printed Functional and Biological Materials on Moving Freeform Surfaces"
    (2020-05-13) Zhu, Zhijie; Guo, Shuang-Zhuang; Hirdler, Tessa; Eide, Cindy; Fan, Xiaoxiao; Tolar, Jakub; McAlpine, Michael C; mcalpine@umn.edu; McAlpine, Michael C; McAlpine Research Group; Tolar Laboratory
    The data set includes the experimental data supporting the results reported in Zhu, Zhijie, Shuang‐Zhuang Guo, Tessa Hirdler, Cindy Eide, Xiaoxiao Fan, Jakub Tolar, and Michael C. McAlpine. "3D printed functional and biological materials on moving freeform surfaces." Advanced Materials, 30(23), 1707495. Conventional 3D printing technologies typically rely on open‐loop, calibrate‐then‐print operation procedures. An alternative approach is adaptive 3D printing, which is a closed‐loop method that combines real‐time feedback control and direct ink writing of functional materials in order to fabricate devices on moving freeform surfaces. Here, it is demonstrated that the changes of states in the 3D printing workspace in terms of the geometries and motions of target surfaces can be perceived by an integrated robotic system aided by computer vision. A hybrid fabrication procedure combining 3D printing of electrical connects with automatic pick‐and‐placing of surface‐mounted electronic components yields functional electronic devices on a free‐moving human hand. Using this same approach, cell‐laden hydrogels are also printed on live mice, creating a model for future studies of wound‐healing diseases. This adaptive 3D printing method may lead to new forms of smart manufacturing technologies for directly printed wearable devices on the body and for advanced medical treatments.
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    Supporting data for "3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors"
    (2020-05-22) Qiu, Kaiyan; Zhao, Zichen; Haghiashtiani, Ghazaleh; Guo, Shuang-Zhuang; He, Mingyu; Su, Ruitao; Zhu, Zhijie; Bhuiyan, Didarul B; Murugan, Paari; Meng, Fanben; Park, Sung Hyun; Chu, Chih-Chang; Ogle, Brenda M; Saltzman, Daniel A; Konety, Badrinath R; Sweet, Robert M; McAlpine, Michael C; mcalpine@umn.edu; McAlpine, Michael C; McAlpine Research Group
    The data set includes the experimental data and the corresponding MRI stereolithography (STL) file supporting the results reported in Kaiyan Qiu; Zichen Zhao; Ghazaleh Haghiashtiani; Shuang-Zhuang Guo; Mingyu He; Ruitao Su; Zhijie Zhu; Didarul B. Bhuiyan; Paari Murugan; Fanben Meng; Sung Hyun Park; Chih-Chang Chu; Brenda M. Ogle; Daniel A. Saltzman; Badrinath R. Konety; Robert M. Sweet; Michael C. McAlpine. 3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors. Adv. Mater. Technol. 2018, 3, 1700235. The design and development of novel methodologies and customized materials to fabricate patient-specific 3D printed organ models with integrated sensing capabilities could yield advances in smart surgical aids for preoperative planning and rehearsal. Here, we demonstrate 3D printed prostate models with physical properties of tissue and integrated soft electronic sensors using custom-formulated polymeric inks. The models show high quantitative fidelity in static and dynamic mechanical properties, optical characteristics, and anatomical geometries to patient tissues and organs. The models offer tissue-like tactile sensation and behavior and thus can be used for the prediction of organ physical behavior under deformation. The prediction results show good agreement with values obtained from simulations. The models also allow the application of surgical and diagnostic tools to their surface and inner channels. Finally, via the conformal integration of 3D printed soft electronic sensors, pressure applied to the models with surgical tools can be quantitatively measured.