CAREER: Multi-functional interlayer-RF resonators as a platform for passive and wireless biosensing

无创、无线的医疗设备或生物传感器已经成为追踪人类表现、生物标志物和健康状况的强大工具。在这类设备中，柔性设备形式的保形护理点接口由于其低尺寸，减轻用户负担以及能够在复杂表面/环境上监测生理参数（即心跳，加速度，葡萄糖等）而变得流行。现有的生物传感器通常存在物理尺寸大、需要电力、寿命短和灵敏度低的问题。这个CAREER项目的目标是研究、设计和开发无线无源射频识别设备（RFID）型生物传感器。这些设备可以连接、嵌入或植入到新的区域，并无线监控它们的宿主环境。这些传感器，连同它们在不同层上开发的传感金属图案，包含一个纳米多孔材料的中间层，在特定化学刺激的存在下，这些材料会吸收、膨胀或变形，导致它们的谐振频率发生变化。这种传感器特性的变化作为宿主环境刺激变化的函数将被用作一种检测机制。新提出的夹层材料可以是膜、分离器、可变形材料、温度/pH/金属响应聚合物等。这些材料中有许多具有长寿命并且没有降解机制。具有可编程灵敏度和选择性的显著改进的保形通用传感器是该项目的目标。这些设备可能以新的方式与生命系统集成，并在无线健康领域实现新的应用。在这个项目中提出的独特的教育和推广计划的重点是为年轻（通常是代表性不足的）学生提供创造力和想象力。本科学生需要学习的潜在技术技能包括：制造经验（计量、光刻、3d打印）、扫描电子显微镜、实验方法、数值/分析建模、数据分析和计算机辅助设计（CAD）。建议通过教授有趣、生物相容/安全的制造程序来培养对STEM的长期兴趣，这些程序可以由所有年龄和技能水平的学生执行。该项目的研究成果将在加州大学欧文分校（UCI），一个西班牙裔服务机构（HSI），通过BuildCamp和FABcamp等项目举办的各种夏季技术营中教授。该项目将开发具有可调灵敏度和选择性的下一代无源无线生物传感器。重点是利用一种传感方式，可以支持本地无线读出和稳健的长期运行。核心传感器由堆叠和谐振耦合的分环线圈（或多圈天线）组成，其中包含层间材料，这些材料会在物理刺激下吸收、膨胀或变形。将研究软材料或纳米多孔材料与金属融合成多功能结构的新制造技术的发展。这将使射频分析生物传感器具有可编程的灵敏度和选择性。该方法将利用能够选择性地从复杂的生物流体中吸收分析物的膜，或者对特定的分析物产生强烈的膨胀反应。四种类型的膜：离子选择性、聚合物气凝胶、葡萄糖反应和改性生物聚合物将被研究作为潜在的层间材料。将研究和分析各自材料的独特电磁和生物相互作用物理如何结合到冲击传感器性能的理论和计算研究。传感器行为的实验研究包括传感器在分析物混合物中的测量，传感器电路的合成，使易于读取，以及阵列作为提高响应的手段的研究。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。

Non-invasive, wireless-enabled medical devices or biosensors have been emerging as powerful tools to track human performance, biomarkers, and wellness. Within this class of devices, conformal, point-of-care interfaces in the form of flexible devices have become popular due to their low form factor, reduced user burden, and ability to monitor physiological parameters (i.e., heartbeat, acceleration, glucose etc.) on complex surfaces/environments. Existing biosensors within such devices often suffer from large physical size, need for power, short lifetime, and low sensitivity. The objective of this CAREER project is to study, design, and develop wireless-enabled passive radio frequency identification device (RFID) type biosensors. These could be attached, embedded, or potentially implanted to new areas and wirelessly monitor their host environments. These sensors, along with their sensing metal patterns developed on different layers, contain an intermediate layer of nanoporous materials that will absorb, swell or deform in the presence of specific chemical stimuli causing their resonant frequencies to change. This change in the sensor property as function of the change in the stimuli of host environment will be used as a detection mechanism. The proposed new interlayer materials could be membranes, separators, deformable materials, temperature/pH/metal-responsive polymers, and more. Many of these materials have long-lifetimes and possess no degradative mechanism. Significantly improved, conformal, versatile sensors with programmable sensitivity and selectivity are the project goals. Such devices could potentially integrate with living systems in new ways and enable new applications in wireless health. The unique education and outreach program proposed in this project is focused on powering the creativity and imagination of younger (and often underrepresented) students. Potential technical skills to be learned by undergraduate students include: fabrication experience (metrology, photolithography, 3-D printing), scanning-electron microscopy, experimental methodology, numerical/analytical modelling, data analysis, and computer aided design (CAD). Creating a long-term interest in STEM by teaching fun, biocompatible/safe fabrication procedures that can be performed by students of all ages and skill levels is proposed. Research efforts of this project will be taught in various summer tech camps run by the University of California Irvine (UCI), a Hispanic Serving Institution (HSI), through programs like BuildCamp and FABcamp. This project will develop next-generation, passive wireless biosensors with tunable sensitivity and selectivity. The focus is on utilizing a sensing modality that can support native wireless read-out and robust, long-term operation. The core sensor is composed of stacked and resonant-coupled split ring coils (or multi-turn antennas) that contain interlayer materials that absorb, swell, or deform in response to physical stimuli. The development of new fabrication techniques to fuse soft or nanoporous materials with metals into multi-functional constructs will be investigated. This will enable RF analytical biosensors with programmable sensitivity and selectivity. The approach will be to utilize membranes that are able to either selectively absorb analytes from complex biofluids, or heavily swell in response to a specific analyte. Four types of membranes: ion-selective, polymer-aerogel, glucose-responsive, and modified biopolymer will be studied as potential interlayer materials. Theoretical and computational studies on how the unique electromagnetic and bio-interactive physics of respective materials combine to impact sensor performance will be studied and analyzed. The experimental studies on sensor behavior include sensor measurement in mixtures of analyte, the synthesis of sensor-circuits that enable facile and accessible read-out, as well as the studying of arraying as a means of enhancing response.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.