CAREER: 2D Nanoelectronic Devices Integrated with Nanofluidic Structures for Biosensing Applications

检测和量化低丰度生物分子的能力对临床诊断和药物开发至关重要。例如，这种能力可以用于早期癌症诊断。表面等离子体共振是这类分析的标准方法，但仍存在灵敏度低、检出限差、分析过程缓慢等缺点。这些限制促使人们努力创造新的纳米级电子生物传感器，以实现低检测限下高效、无标签、多路生物分子定量。本提案中描述的工作旨在通过将新兴的二维（2D）纳米电子材料集成到纳米/微流体结构中来构建一种新的生物传感器。这种二维材料集成的纳米流体生物传感器如果成功实现，将极大地提高疾病相关生物标志物检测和定量的能力。这里提出的工作对于实现新的成本/时间有效的免疫分析芯片具有重要的潜力，可以满足全球对疾病诊断和分层新能力的需求，并提高美国的工业竞争力。除了提高基本的学术研究能力，拟议的教育/研究综合项目将为广泛的人群提供相关的知识和技术技能，包括K-12学生/教育工作者、本科生、毕业生，以及来自代表性不足和少数群体的学生。具体而言，拟议的教育/推广计划将包括一个新的课后计划，指导K-12学生学习与微流体/电子集成生物传感器相关的基础知识；扩大与密歇根大学学术项目的合作，为本科生提供研究机会；将与纳米流体和纳米电子学相关的新主题引入研究生/本科课程。拟议的设备导向研究旨在利用二维材料的优越电子/结构特性和纳米流体设备中独特的电动力学，以实现单分子水平的低丰度生物分子检测。为了实现这一目标，PI将克服与纳米电子学、纳米流体学和生物传感相关的一系列挑战。具体而言，(i)创建一种纳米制造方法，能够将纳米/微流体结构与纳米级2D晶体管集成，并生产大型器件阵列，从而实现设想的生物测定所需的器件小型化和多路复用能力。（ii）创建生物功能化途径，实现纳米电子传感器的选择性功能化，并创建一种电动方法，有效地将目标分子运送/浓缩到传感区域，这对于防止非特异性吸附和获得低丰度分子定量所需的低检测限至关重要。非特异性吸附将通过使用特定的阻塞缓冲液和优化纳米流体结构进一步抑制。（iii）全面了解所提出器件的纳米电子和纳米流体特性之间的复杂相互作用，包括生物分子向传感器的电动传输速率，纳米流体环境对生物分子浓度分布的影响，响应生物偶联过程的晶体管参数的动态行为，分析物-受体对的解离常数与传感器的检测限/特异性的关系。（iv）开发能够快速确定多种生物分子浓度的多路设备阵列。所提出的生物传感器，如果成功创建，可以首先作为一个通用的设备平台，分析广泛的分子相互作用。特别是，它可以用于测量各种分析物-受体对相互作用的亲和力和动力学，灵敏度低至飞摩尔浓度（或单分子水平检测限）。这些知识将极大地促进对复杂细胞事件的理解，如癌症和免疫反应的发展。所提出的生物传感器的大阵列最终将允许快速（分钟级样品到结果的经过时间），高度精确（单分子水平检测限）的临床诊断免疫分析。所提出的生物传感器的检测原理完全是电的，不需要传统荧光分析所需的任何片外光学。这将使医疗点应用程序所需的独立设备功能成为可能。

The ability to detect and quantify low-abundance biomolecules is critical for clinical diagnostics and drug development. For example, such ability can be used for early-stage cancer diagnosis. Surface plasmon resonance is the standard method for such analysis, but it still suffers from drawbacks such as low sensitivity, poor detection limit, and slow analysis process. These limitations motivate the efforts to create new nanoscale electronic biosensors for realizing efficient, label-free, multiplexing biomolecule quantification at low detection limits. The work described in this proposal aims at constructing a new biosensor by integrating emerging two-dimensional (2D) nanoelectronic materials into nano/microfluidic structures. Such a 2D-material-integrated nanofluidic biosensor, if successfully realized, will greatly advance the capability for illness-related biomarker detection and quantification. The work proposed here holds significant potential for realizing new cost/time-effective immunoassay chips that can address global needs for new capabilities for diagnosis and stratification of diseases and US industrial competitiveness. Beyond advancing fundamental academic research capabilities, the proposed education/research-integrated program will provide relevant knowledge and technical skills to a broad range of people, including K-12 students/educators, undergraduates, graduates, as well as students from underrepresented and minority groups. Specifically, the proposed education/outreach program will include a new after-school program for instructing K-12 students to learn basic knowledge related to microfluidic/electronic-integrated biosensors; extending the collaboration with academic programs at the University of Michigan to provide research opportunities for undergraduates; introducing new topics related to nanofluidics and nanoelectronics into graduate/undergraduate courses.The proposed device-oriented research seeks to leverage superior electronic/structural properties of 2D materials and unique electrokinetics in nanofluidic devices for enabling low-abundance biomolecule detection at single-molecule levels. To realize this goal, the PI will overcome a series of challenges related to nanoelectronics, nanofluidics, and biosensing. Specifically, (i) create a nanofabrication method capable of integrating nano/microfluidic structures with nanoscale 2D transistors and producing large device arrays, therefore enabling the device miniaturization and multiplexing capability required for the envisaged bio-assays. (ii) Create a biofunctionalization route for realizing the selective functionalization of nanoelectronic sensors and an electrokinetic approach for efficiently transporting/concentrating target molecules toward the sensing areas, which are critical for preventing non-specific adsorption and obtaining a low limit-of-detection required for low-abundance molecule quantification. Non-specific adsorption will be further suppressed through using specific blocking buffers and optimizing nanofluidic architectures. (iii) Obtain a comprehensive understanding of the complex interactions between nanoelectronic and nanofluidic characteristics of the proposed device, which include electrokinetic transport rates of biomolecules toward sensors, effects of nanofluidic environments on biomolecule concentration distributions, dynamic behaviors of transistor parameters in response to bioconjugation processes, and relationship between the dissociation constant of an analyte-receptor pair and the sensor's detection limit/specificity. (iv) Develop multiplexed device arrays capable of rapidly determining multiple biomolecule concentrations. The proposed biosensor, if successfully created, can firstly serve as a generic device platform for analyzing a broad range of molecular interactions. Especially, it can be used for measuring the affinities and kinetics of various analyte-receptor pair interactions with sensitivities down to femtomolar concentrations (or single-molecule-level detection limits). Such knowledge will greatly advance the understanding of complex cellular events, such as the development of cancers and immune-responses. The large arrays of the proposed biosensors would eventually allow for rapid (minute-scale sample-to-result elapsed times), highly precise (single-molecule-level detection limits) immunoassay for clinical diagnostics. The detection principle of the proposed biosensor is completely electrical and does not need any off-chip optics required for conventional fluorescence-based assays. This will enable stand-alone device capability required for point-of-care applications.