NER: Acoustic Radiation Pressure Driven Atomic Force Microscope for Fast Imaging and Parallel Sensing of Biological and Chemical Processes at the Nanoscale

在液体环境中工作的能力一直是原子力显微镜(AFM)在纳米科学和纳米技术的最新进展中发挥无可争议的作用的关键原因之一。这种能力不仅使生物样品成像和在纳米尺度上观察生物和化学过程成为可能，而且在生物传感和蛋白质组学领域也导致了许多基于微悬臂梁的器件的发展。液体环境对AFM的操作提出了巨大的挑战，特别是在动态成像模式下，如轻拍模式和快速成像应用。与空气相比，液体为机械扰动提供了更有效的耦合介质。因此，由于样品和致动器结构周围充满液体的空腔，AFM悬臂梁的常规压电驱动会产生虚假的共振信号。一些基于磁性、静电和薄膜压电技术的新型驱动器已经被开发出来解决这个问题，但这些方法严重限制了可用于实验的悬臂梁和液体的类型。此外，这些方法不适合于驱动阵列中的单个悬臂梁，这是生物传感应用所需的重要能力。本探索性研究方案旨在消除使用新型微悬臂驱动技术实现液体中多功能AFM的这些重要障碍。该技术利用准直高频(100-400 MHz)声波对AFM悬臂梁产生的声辐射力，在DC-MHz频率范围内驱动悬臂梁。使用这项技术的有希望的初步结果最近已经获得，并在提案中提出。在这些结果的基础上，提出了以下目标：-声辐射压力(ARP)执行器的单个和阵列的设计和微制造：执行器将使用薄的氧化锌薄膜在硅衬底上制造，以产生250 MHz左右的声波，硅微加工技术将被用于制造声菲涅尔透镜，将声束引导到AFM悬臂上。-将该执行器与广泛可用的商业AFM系统集成：将制造包括ARP执行器的流体单元，并使用适当的电子设备在商业AFM系统上使用。-评估集成执行器的能力和局限性：ARP执行器在快速成像方面的性能，以及阵列操作将进行测试，并与传统方法进行比较。-ARP致动器可能的不利影响的研究：将在几个重要样本上探索高频声波与生物过程的相互作用，并相应地改进致动器设计。该项目的成功实施将对纳米科学和工程的许多领域产生影响，因为它将帮助研究人员测试和实施创新想法，并在纳米尺度上探索更广泛的生物和化学过程。

0210415DegertekinThe capability of operating in liquid environments has been one of the key reasons for the atomic force microscope's (AFM) indisputable role in the recent advances in nanoscience and nanotechnology. This capability has not only enabled imaging biological samples and observation of biological and chemical processes at the nanoscale, but also led to the development of many microcantilever-based devices in the area of biosensing and proteomics.The liquid environment presents significant challenges to the operation of the AFM, especially in dynamic imaging modes such as tapping mode, and fast imaging applications. As compared to air, the liquids provide a more efficient coupling medium for mechanical perturbations. Hence regular piezoelectric actuation of the AFM cantilever results in spurious resonant signals due to the liquid filled cavity surrounding the sample and the actuator structure. Several novel actuators, based on magnetic, electrostatic, and thin-film piezoelectric techniques have been developed to solve this problem, but these methods severely limit the type of cantilevers and liquids that can be used for experiments. Furthermore, these methods are not suitable for actuation of individual cantilevers in an array, an important capability required for biosensing applications.This exploratory research proposal aims to remove these important obstacles in the implementation of a versatile AFM for applications in liquids using a novel microcantilever actuation technique. The technique uses the acoustic radiation force generated by collimated high frequency (100-400MHz) acoustic waves directed to the AFM cantilever to actuate the cantilever in the DC-MHz frequency range. Promising initial results using the technique have been recently obtained and presented in the proposal. Based on these results, the following objectives are proposed:-Design and microfabrication of individual and arrays of acoustic radiation pressure (ARP) actuators: The actuators will be fabricated on silicon substrates using a thin Zinc Oxide film to generate acoustic waves around 250MHz and silicon micromachining techniques will be used to fabricate acoustic Fresnel lenses to direct the acoustic beams to AFM cantilevers.-Integration of the actuator to a widely available commercial AFM system: A fluid-cell including an ARP actuator will be manufactured and used on a commercial AFM system with appropriate electronics.-Evaluation of the capabilities and limitations of the integrated actuator: The performance of the ARP actuator for fast imaging, as well as array operation will be tested and compared with conventional methods.-Study of possible adverse effects of the ARP actuator: Interaction of high frequency acoustic waves with biological processes will be explored on several important samples and the actuator design will be improved accordingly. Successful implementation of this project will impact numerous areas of nanoscience and engineering, because it will help researchers in the testing and implementation of innovative ideas and in probing a wider variety of biological and chemical processes at the nanoscale.