Towards Internet of Implantable Things: A Micro-Scale Magnetoelectric Intra-Body Communication Platform

具有传感和驱动能力的植入式医疗设备无线连接网络有望实现前所未有的实时医疗监测和治疗，从而改变社会健康和福祉。在这样的系统中，植入物可以测量关键的物理和生理参数，如移动性、心率、神经活动和化学。基于这些数据，该系统可以在许多应用中预防重大健康事件的发生或治疗疾病，如药物输送、闭环神经假体等。为了实现这一愿景，从传统的独立高侵入性植入物到微型植入物的无线连接网络（即可植入物互联网）的范式转变至关重要。在目前最先进的体内通信技术中存在着许多未解决的挑战，包括射频、感应、超声和人体通信。这些挑战包括：高功耗、短通信范围、低数据速率和大型植入式发送/接收传感器。需要一种新型的微尺度植入式方法，使低功耗的体内通信能够以每秒兆位（Mbps）的速率进行长距离（米）通信。拟议的研究将展示一个独特的构建块，用于一套全面的无线连接微创植入物，将实现实时医疗监测和治疗。它将为开展前所未有的神经科学和电生理学实验提供机会，以解决有关复杂神经系统的最基本问题。该项目还包括一个重要的教育和推广组成部分，利用研究的多学科性质来影响K12教师和学生，少数民族，本科生和研究生。K-12教师和学生将在夏季接待，并支持多学科课堂研究项目，工程模块，以及与拟议研究密切相关的实践机会。拟议的植入式物联网被设想为微创、完全无线和高度连接，以解决当前最先进的体内通信技术中存在的挑战，例如高功耗、短通信范围、低数据速率和笨重的发射器/接收器。该项目的主要目标是通过使用mhz范围的磁场和可植入的微尺度磁电换能器，在小型生物医学植入物网络之间实现宽带、远程和低功耗无线通信。总体目标是在显著减小植入物尺寸的同时，提供几Mbps的数据速率和全身通信范围，能耗为皮焦耳/位（pJ/bit）。低频磁场因其在人体组织中的吸收极低和安全性而具有吸引力。将进行系统的研究，以了解在数十兆赫兹工作的可植入微型磁电换能器的基本行为，并与定制设计的基于脉冲的收发电路接口，以实现节能和稳健的体内通信。通过创新的磁电换能器和电路设计，将克服与植入物串扰、对准、取向和组织相互作用不确定性有关的影响。将进行广泛的表征以阐明材料微观结构和各向异性、换能器工作模式、对准、取向和组织相互作用对性能的影响。本文将开发并实验验证不同组织介质下磁电换能器的高精度计算和电路模型，这将为广泛的系统设计提供基础。该计划将为一种新的调制技术提供基础，称为超声谐波调制，以及用于微尺度磁电换能器的收发芯片。这将导致一个一流的微尺度植入式平台，用于在安全的mhz范围频率下信道化节能的米范围通信。系统级演示使用不同的磁电换能器（尺寸范围为0.1-1毫米）和频率（10-100 MHz），以Mbps的速度在米范围内进行通信，功耗为pJ/bit，这将为植入式物联网奠定基础。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Towards Internet of Implantable Things: A Micro-Scale Magnetoelectric Intra-Body Communication Platform Wirelessly connected networks of implantable medical devices with sensing and actuation capability hold the promise of unprecedented real-time healthcare monitoring and therapies that can transform societal health and well-being. In such systems, implants can measure critical physical and physiological parameters, such as mobility, heart rate, neural activity, and chemistry. Based on this data, the system can act to prevent the onset of critical health events or treat diseases in many applications, such as drug delivery, closed-loop neural prostheses, etc. For this vision to be successful, a paradigm shift from conventional standalone highly invasive implants to wirelessly connected networks of miniaturized implants (i.e., Internet of Implantable Things) is of paramount importance. Multiple unresolved challenges exist within current state-of-the-art techniques for intra-body communication that includes radio frequency, inductive, ultrasound, and human body communication. These challenges are: high power consumption, short communication range, low data rate, and large implantable transmitter/receiver transducers. Novel micro-scale implantable methods that enable low-power intra-body communication across long distances (meter) at Mega bits-per-second (Mbps) rates are needed. The proposed research will demonstrate a unique building block for a comprehensive set of wirelessly connected minimally invasive implants that will enable real-time healthcare monitoring and therapies. It will open opportunity for conducting unprecedented neuroscience and electrophysiology experiments that address the most basic questions about the complex nervous system. This program also includes a significant educational and outreach component by taking advantage of the multidisciplinary nature of the research to impact K12 teachers and students, minorities, and undergraduate and graduate students. K-12 teachers and students will be hosted in summers and supported with multidisciplinary classroom research projects, engineering modules, and hands-on opportunities closely coupled to the proposed research. The proposed Internet of Implantable Things are envisioned to be minimally invasive, fully wireless, and highly connected to address existing challenges within current state-of-the-art techniques for intra-body communication, such as high-power consumption, short communication range, low data rate, and bulky transmitters/receivers. The main objective of this program is to enable wideband, long-range, and low power wireless communication among a network of miniaturized biomedical implants through the use of MHz-range magnetic fields coupled with implantable micro-scale magnetoelectric transducers. The overarching target is to simultaneously provide several Mbps data rate and whole-body communication range with pico-joule-per-bit (pJ/bit) level of energy consumption while dramatically reducing the implant's size. Low-frequency magnetic fields are attractive because of their very low absorption in human tissue and safety. Systematic investigations will be conducted to understand the fundamental behavior of implantable micro-scale magnetoelectric transducers operating at tens of MHz and interfaced with custom-designed pulse-based transceiver circuits for energy-efficient and robust intra-body communication. Effects related to implants' crosstalk, alignment, orientation, and tissue interaction uncertainties in ambulatory subjects will be overcome through innovative magnetoelectric transducer and circuit design. Extensive characterization will be conducted to elucidate the influence of material microstructure and anisotropy, transducer operating mode, alignment, orientation, and tissue interactions on the performance. High accuracy computational and circuit models for magnetoelectric transducers at different tissue medium will be developed and experimentally validated, which will serve as a basis for broad range of system design. The program will provide foundational basis for a novel modulation technique, termed Ultrasound Harmonic Modulation, along with a transceiver chip for micro-scale magnetoelectric transducers. This will lead to a first-in-class micro-scale implantable platform for channelized energy-efficient meter-range communication at safe MHz-range frequencies. System-level demonstrations with different magnetoelectric transducers (dimensional range of 0.1-1 millimeter) and frequencies (10-100 MHz) enabling communication up to meter range at Mbps with pJ/bit power consumption will establish the fundamental basis for the Internet of Implantable Things.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.