We present a multifunctional packaging technique for implantable microdevices. The packaging is composed of 3D printed bulk piezoelectric barium titanate (BaTiO3) ceramic with unique geometry shaped (i.e., regular convex polyhedrons; Platonic solid). The BaTiO3 ceramic provides not only a seamless packaging for essential electronics but also a power source for those electronics through the conversion of incoming ultrasound. Ultrasound has been an attractive powering source for many implantable microdevices . However, most ultrasonic receivers are rectangular or disc, not in ideal form factors; ultrasound is often deflected within the path, and the miniature implants might shift and rotate, resulting in an angular misalignment. Tailoring a three-dimensional polyhedral architecture (i.e., Platonic solid) for an mm-scale ultrasonic receiver can dramatically enhance its omnidirectionality. Utilizing the 3D printing technique, we devised a dodecahedron shaped BaTiO3 ceramic with the center void space for electronics embodiment. As a proof of concept, an LC (inductor-capacitor pair) resonator is implemented as a representative implantable microdevice [2, 3]. The LC resonator has been utilized in physiological sensing by employing either a capacitive or inductive sensor. These sensors are typically powered by inductive coupling or batteries which can be impracticable when the implant is placed deep inside the tissues.more »
Robotic Replica of a Human Spine Uses Soft Magnetic Sensor Array to Forecast Intervertebral Loads and Posture after Surgery
Cervical disc implants are conventional surgical treatments for patients with degenerative disc disease, such as cervical myelopathy and radiculopathy. However, the surgeon still must determine the candidacy of cervical disc implants mainly from the findings of diagnostic imaging studies, which can sometimes lead to complications and implant failure. To help address these problems, a new approach was developed to enable surgeons to preview the post-operative effects of an artificial disc implant in a patient-specific fashion prior to surgery. To that end, a robotic replica of a person’s spine was 3D printed, modified to include an artificial disc implant, and outfitted with a soft magnetic sensor array. The aims of this study are threefold: first, to evaluate the potential of a soft magnetic sensor array to detect the location and amplitude of applied loads; second, to use the soft magnetic sensor array in a 3D printed human spine replica to distinguish between five different robotically actuated postures; and third, to compare the efficacy of four different machine learning algorithms to classify the loads, amplitudes, and postures obtained from the first and second aims. Benchtop experiments showed that the soft magnetic sensor array was capable of precisely detecting the location and amplitude more »
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