NIRT: Enhancing the Sensitivity and Stability of Biosensors by Novel Nanostructures

在这个项目中，我们建议开发纳米级3D结构，并使用纳米结构作为3D基底来解决生物传感中的问题。为了实现这一目标，我们将扩展我们新开发的纳米纤维技术-掠射角沉积（GLAD）-以制造纳米级3D柱，从而控制纳米柱（或纳米棒）的大小，高度，间距，形状和位置，并实现多层纳米棒。这一发展将提供几个独特的功能，以满足生物传感应用的需求。我们将利用固定化酵素的方法，将奈米棒功能化，进而衍生出奈米葡萄糖传感器，我们的目标是：（1）制作出尺寸、间距、高度、形状、位置等参数可控的奈米结构，以制作奈米电极;（2）将酵素固定在奈米结构上，以达到高灵敏度与高活性;（3）将顶层纳米棒的尺寸和间距控制在20 nm以内，从而可以实现机械过滤以用于过滤;（4）使用自组装单层（SAM）技术钝化顶层纳米棒以进一步改善过滤;以及（5）制备原型葡萄糖传感器并评估其灵敏度、稳定性和过滤行为。(1)该项目的新奇之处在于：（1）利用多层、垂直排列和高纵横比的金属纳米棒作为三维电极，葡萄糖传感器的灵敏度和响应时间将显著提高;（2）通过控制顶层纳米棒的尺寸和间距小于20 nm，将实现防止蛋白质渗透的机械过滤;（3）通过顶层纳米棒的选择性钝化（使用特定的SAM，例如Oligo（乙二醇）封端的烷硫醇），将防止进一步的蛋白质吸附;以及（4）整个开发过程与大规模微制造过程兼容。因此，我们预计，通过将新型纳米结构集成到生物传感应用中，我们将能够解决灵敏度，生物污染（通过化学钝化和机械过滤）和小型化的问题。建议的项目是可行的，因为它完全在所有PI的专业知识范围内。(2)拟议活动产生的更广泛影响：拟议项目旨在整合生物技术和纳米技术，以促进这一新兴前沿领域的基础知识，并获得有益的应用，造福公众和人类。该项目的成功不仅将为开发高性能葡萄糖传感器提供一种新技术，而且还将为开发其他类型的化学和生物传感器的纳米结构提供知识基础、基础和技术基础。它还将为将多层纳米结构（如纳米膜）纳入多功能和多物种化学和生物传感的实现开辟新的机会。该项目还将为研究生和本科生提供独特的机会，以获得材料科学，纳米技术和生物工程多学科领域的宝贵实践经验和培训。

In this project, we propose to develop nanoscale 3D structures and use the nanostructures as 3D substrates to address problems in biosensing. To achieve this objective, we will expand our newly developed nanofabrication technique - glancing angle deposition (GLAD) - to fabricating nanoscale 3D pillars such that the size, height, spacing, shape and location of the nanopillars (or nanorods) will be controlled, and multiple layers of nanorods will be realized. This development will provide several unique features to suit the needs for biosensing applications. We will derive nanoscale glucose sensors by functionalizing the nanorods through enzyme immobilization.With this proposed project, we aim to achieve the following specific objectives: (1) to fabricate nanostructures with controlled parameters, such as size, spacing, height, shape and location, for developing nanoelectrodes; (2) to immobilize enzymes onto well-prepared nanostructures to achieve high sensitivity and activity; (3) to control the size and separation of the top layer nanorods to be within 20 nm, so that a mechanical filtration can be realized for antifouling; (4) to passivate the top layer nanorods using self-assembly monolayer (SAM) technique to further improve antifouling; and (5) to fabricate prototype glucose sensors and assess their sensitivity, stability and antifouling behavior.(1) The intellectual merit of the proposed activity: The novelty of this project lies in the following areas: (1) with the multilayer and vertically aligned and high aspect-ratio metallic nanorods serving as 3D electrodes, the sensitivity and response time of the glucose sensors will be significantly improved; (2) with the size and spacing of the top-layer nanorods controlled less than 20 nm, a mechanical filtration to prevent protein penetration will be achieved; (3) with selective passivation (using a specific SAM, such as Oligo(ethylene glycol)-terminated alkanethiols) of the top-layer nanorods, further protein adsorption will be prevented; and (4) the entire development process is compatible with mass microfabrication procedures. Thus, we anticipate that by integrating the novel nanostructures into biosensing applications, we will be able to address concerns of sensitivity, biofouling (via both the chemical passivation and mechanical filtration), and miniaturization. The proposed project is feasible because it is well within the expertise of all PIs.(2) The broader impacts resulting from the proposed activity: This proposed project seeks to integrate biotechnology and nanotechnology for advancing fundamental knowledge in this nascent frontier, and for deriving useful applications to benefit the general public and humankind. The success of this project will not only lead to a new technique for developing high performance glucose sensors, but also serve as a knowledge base, groundwork, and technical foundation for developing nanoscale structures for other types of chemical and biological sensors. It will also open new opportunities for incorporating multilayer nanostructures (as nano-membranes) into realization of multifunctional and multi-specie chemical and biological sensing. This project will also provide unique opportunities for both graduate and undergraduate students to gain precious hands-on experience and training in the multidisciplinary fields of materials science, nanotechnology, and biological engineering.