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

迈向可植入物联网：微型磁电体内通信平台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，可以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防止严重健康事件的发生或治疗疾病，如药物输送、闭环神经假体等。要使这一愿景成功，从传统的独立高侵入性植入物向微型植入物的无线连接网络(即可植入物联网)的范式转变是至关重要的。包括射频、感应、超声波和人体通信在内的当前最先进的体内通信技术中存在多个尚未解决的挑战。这些挑战是：高功耗、短通信距离、低数据速率和大型植入式发射/接收换能器。需要新的微尺度可植入方法，以实现以兆比特/秒(Mbps)速率进行长距离(Meter)的低功率体内通信。拟议的研究将展示一套全面的无线连接微创植入物的独特构建块，这些植入物将实现实时医疗监测和治疗。它将为进行史无前例的神经科学和电生理学实验提供机会，这些实验解决了关于复杂神经系统的最基本问题。该计划还包括一个重要的教育和推广部分，利用研究的多学科性质来影响K12教师和学生、少数族裔以及本科生和研究生。K-12的教师和学生将在暑假接受接待，并为他们提供与拟议研究密切相关的多学科课堂研究项目、工程模块和实践机会。拟议的可植入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，如高功耗、短通信距离、低数据速率和庞大的发射器/接收器。该计划的主要目标是通过使用MHz范围的磁场和可植入的微型磁电换能器，在微型生物医学植入物网络之间实现宽带、远程和低功率的无线通信。总体目标是同时提供几Mbps的数据速率和具有皮焦耳/比特(PJ/比特)级别的能量消耗的全身通信范围，同时显著减小植入物的尺寸。低频磁场之所以吸引人，是因为它在人体组织中的吸收率很低，而且很安全。将进行系统的研究，以了解可植入的微尺度磁电换能器的基本行为，这些换能器在数十MHz的频率下工作，并与定制设计的基于脉冲的收发电路接口，以实现高能效和强大的体内通信。通过创新的磁电换能器和电路设计，移动受试者中与植入物的串扰、对准、定向和组织相互作用不确定性相关的影响将被克服。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、排列、取向和组织相互作用对性能的影响。将建立不同组织介质中磁电换能器的高精度计算和电路模型，并进行实验验证，这将作为广泛的系统设计的基础。该计划将为一种名为超声谐波调制的新调制技术以及用于微型磁电换能器的收发芯片提供基础。这将带来一流的微尺度可植入平台，用于在安全MHz范围的频率下进行信道化能效米程通信。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)进行系统级演示，以PJ/比特功耗实现高达米范围的通信，将为可植入物联网奠定基本基础。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.