CAREER: Integrated Research and Education on Self-Activated, Transparent Harmonics-Based Wireless Sensing Systems Using Graphene Bioelectronics

物联网最近在具有成本效益和长期健康监测方面越来越受欢迎，通过收集和分析来自可穿戴微和纳米级传感器的生物信息来实现。虽然无电池的微型传感器可以实现廉价，长寿命和免维护的操作，这些微型传感器通常遭受不必要的电磁干扰，如杂波，回波和多径衰落，这大大降低了信噪比和无线询问范围。为了克服这些挑战，本研究项目将研究一类新的自供电，化学调谐谐波应答器作为无线生物传感器。谐波生物传感器由全石墨烯天线和集成电路（石墨烯基本上是石墨的单原子层）组成，其可以被制成透明的、重量轻的、柔性的和生物相容性的用于医学应用，从而使得接触透镜传感器用于低成本、便携式和连续诊断病原体细菌、蛋白质和多功能生物分子标记物成为可能。所提出的无线生物感测技术可导致各种应用，例如检测病毒性眼部感染、眼表肿瘤和眼内压。此外，该项目还将把研究纳入韦恩州立大学的新课程和外联活动中（例如，ReBUILDetroit计划，Richard Barber跨学科研究计划和WSU STEM日），用于在底特律大都市区招募代表性不足的K-12学生，并促进他们对从事射频（RF）工程和生物医学电子学职业的兴趣。本研究项目的目标是研究基于全石墨烯射频和生物电子学的低噪声、节能的无线微传感器系统。该研究的关键科学进展在于基于谐波的生物传感技术，该技术使用完全无源和化学可重构的应答器作为谐波生物传感器，以实现实时和远程无线生物传感。谐波生物传感器与传统的背向散射传感器有着本质的不同，它发射和检测的信号频率正交，可以实现更远的探测距离，从而有效地对抗电磁干扰和人体背向散射杂波。谐波生物传感器可以用简单的基于石墨烯的生物电子电路来实现，该电路基于石墨烯晶体管的独特的双极和可调谐的电子特性，将生物传感器和倍频器的功能结合到单个模块中。此外，这种生物敏感的RF应答器可以连接到放置在柔性生物相容性基底上的透明双频带石墨烯天线。石墨烯谐波生物传感器上的生物分子（例如传染性或生物威胁剂）的选择性结合可以通过发射单调RF信号并检测反向散射的二次谐波的强度来无线监测，因为频率转换效率被生物分子浓度改变。如果成功的话，这种紧凑透明的石墨烯谐波生物传感器可以集成在软接触透镜上，灵敏地检测目标病原体细菌、传染因子、疾病或感兴趣的代谢变化，并在没有任何电源或复杂电路的情况下无线传输数据。随着进一步的发展，拟议中的无线生物传感器可以在医疗保健监测中产生广泛的影响。该奖项反映了NSF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。

The internet-of-things has recently gained popularity in the cost-effective and long-term health monitoring, enabled by collecting and analyzing biological information from wearable micro- and nano-scale sensors. Although battery-free micro-sensors can achieve inexpensive, long-lived and maintenance-free operation, these miniature sensors usually suffer from unwanted electromagnetic interferences, such as clutters, echoes, and multipath fading, which greatly reduce the signal-to-noise ratio and the wireless interrogation range. To surmount these challenges, this research project will investigate a new class of self-powered, chemically-tuned harmonic transponders as wireless biosensors. The harmonic biosensor consists of all-graphene antenna and integrated circuit (graphene is, basically, a single atomic layer of graphite), which can be made transparent, light-weight, flexible, and biocompatible for medical applications, thus making possible a contact lens sensor for low-cost, portable, and continuous diagnosis of pathogen bacteria, proteins, and versatile biomolecular markers. The proposed wireless bio-sensing technology may lead to various applications, such as detection of viral eye infections, ocular surface tumors, and intraocular pressure. In addition, the project will also integrate the research into the new courses and outreach activities in Wayne State University (e.g., ReBUILDetroit Program, Richard Barber Interdisciplinary Research Program, and WSU STEM Days) for recruiting under-represented and K-12 students in the Detroit metropolitan area and promoting their interest in pursuing a career in radio-frequency (RF) engineering and biomedical electronics. The goal of this research project is to investigate the low-noise, energy-efficient wireless micro-sensor system based on all-graphene RF- and bio-electronics. The key scientific advance of this research lies in the harmonics-based bio-sensing technique, which uses a fully passive and chemically reconfigurable transponder as a harmonic biosensor to achieve real-time and long-range wireless bio-sensing. Fundamentally different from conventional backscatter sensors, the harmonic biosensor, launching and detecting signals of orthogonal frequencies, can enable longer detection range against electromagnetic interferences and human-body backscatter clutters. The harmonic biosensor can be realized with a simple graphene-based bioelectronic circuit which combines functions of a biosensor and a frequency multiplier into a single module, based on the unique ambipolar and tunable electronic properties of graphene transistors. Moreover, this bio-sensitive RF transponder can be connected to a transparent, dual-band graphene antenna placed onto the flexible biocompatible substrate. The selective binding of biomolecules, such as infectious or bio-threat agents, on the graphene harmonic biosensor can be wirelessly monitored by launching a monotone RF signal and detecting the strength of the backscattered second harmonic, as the frequency conversion efficiency is altered by the biomolecular concentration. If successful, the compact and transparent graphene harmonic biosensor can be integrated on the soft contact lens to sensitively detect targeted pathogen bacteria, infectious agents, diseases, or metabolic changes of interest, and wirelessly transmit data without any power source or sophisticated circuit. With further development, the proposed wireless biosensors can have broad impacts in healthcare monitoring.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.