IDBR: Development of Higher Eigenmode Ultrasound Bioprobe for Sub-Cellular Biological Imaging

在生物学中，迫切需要创新和非侵入性成像模式，特别是识别疾病状态的早期表现和潜在的基于细胞的治疗方法的功效。西北大学的这个项目将有助于开发用于亚细胞生物成像的更高本征模式的“超声生物探针”。本项目的目标是开发具有高次谐波功能的超声生物探针，以在生理条件下以纳米级分辨率检测和跟踪亚细胞缺陷。预期的应用将研究内皮细胞在细胞转染下的动力学，以开发早期急性肺损伤的潜在治疗方法。它将进一步扩展到研究肿瘤细胞在其发展开始时的进展。在超声生物探针中，悬臂梁监测对表面声波的扰动，特别是它们的相位，其携带关于由于它们各自的粘弹性特性的差异而在样本声波的散射中反射的嵌入或掩埋的子结构的信息。由于亚表面纳米结构/缺陷的存在而引起的体波的振幅和相位的变化以及近表面的变化影响由悬臂检测的差频信号（拍频）的振幅和相位。这些变化用于创建由表面下和近表面特征/缺陷生成的空间映射。为了实现这些努力，需要一种方式来结合联合收割机扫描探针显微镜硬件，功能电子器件和其集成到FPGA（现场可编程门阵列）的同时生成和检测的多个谐波扫描使用LabVIEW代码。通过利用扫描探针显微镜的纳米级分辨率和使用更高次谐波，这种创新方法可以提供一种新的方式来接近实时地执行活细胞的亚细胞生物成像，不受传统电子显微镜方法中提到的挑战的限制，这些方法需要化学固定细胞或冷冻保存和传统的共聚焦/共聚焦荧光显微镜需要荧光标记来成像并具有微尺度分辨率超声生物探针在纳米尺度上检测特征的能力对于研究用质粒转染的人肺动脉内皮细胞的纳米力学具有重要意义。这将有助于了解如何调节内皮细胞的结构安排，导致肺血管系统的屏障功能特性，并协助治疗目标。该项目的更广泛影响有望在生理可行条件下为生物和软结构的高分辨率非破坏性和非侵入性成像开辟新的前景。超声生物探头将被定位为向国外用户群提供所开发的技术。一旦开发完成，其他机构将可以使用该技术，从而扩大其用户基础，将生命科学包括在内。在本科教材中，PI？s将使用这个研究项目的例子来强调工程和物理原理的整合是如何融入真实的生物研究的。PI？s将通过中西部和芝加哥公共机构的科学芝加哥计划，促进妇女和其他少数民族积极参与科学，并参与对小学的课堂访问。教育计划的重点是开发亚细胞成像教学模块，其中包括实验室演示和课堂教程。 教育目标将通过以下方式实现：（a）提供实践和团队经验，以促进积极和协作学习;（B）使有前途的本科生有机会在亚细胞生物成像的新兴领域进行研究，以及（c）通过最低限度教育，（纳米技术少数民族实习）计划，为本科生提供机会，参与纳米技术领域的实践研究。该奖项由CBET/生物光子学计划共同资助，生物研究仪器开发（IDBR）

There is an acute and timely need for innovative and non-invasive imaging modalities in biology, especially to identify early manifestation of disease state, and efficacy of potential cell-based therapeutics. This project at Northwestern University will help develop higher eigenmode "Ultrasound Bioprobe" for sub-cellular biological imaging. The objective of this project is to develop Ultrasound Bioprobe with higher order harmonics capabilities to detect and track subcellular defects at nanoscale resolution under physiological conditions. Anticipated applications will investigate the dynamics of endothelial cells under cellular transfection to develop potential therapeutics for acute lung injuries in the early stage. It will further be extended to study the progression of tumorous cells at onset of their development. In Ultrasound Bioprobe, the cantilever monitors the perturbation to the surface acoustic waves, especially their phase, which carry information about embedded or buried sub-structures reflected in the scattering of specimen acoustic waves due to the difference in their respective viscoelastic properties. Variations in the amplitude and phase of the bulk wave due to the presence of the sub-surface nanostructures/defects as well as the variations in near surface affect the amplitude and the phase of the difference frequency signal (beats) which is detected by cantilever. These variations are used to create spatial mappings generated by subsurface and near-surface features/defects. To realize these efforts requires a way to combine scanning probe microscopy hardware,functional electronics and its integration into an FPGA (field programmable gate arrays) for simultaneous generation and detection of multiple harmonics in scan using labVIEW codes. By leveraging the nanoscale resolution of scanning probe microscope and use of higher order harmonics, this innovative approach may provide a new way to perform sub-cellular biological imaging of living cells in close to real-time, uninhibited by traditionally cited challenges in electron microscopy methods that require chemically fixing of the cells or cryo preservation and conventional confocal/fluorescent microscopies that require fluorescent tags to image and have micro scale resolutionThe ability of the Ultrasound Bioprobe to detect features at nanometer scale has important implications to study the nanomechanics of human pulmonary artery endothelial cells which are transfected with plasmid. It will help understand how to regulate endothelial cell structural arrangements that result in the barrier function properties of the pulmonary vasculature and to assist therapeutics targets. The Broader Impact of the project promises to open new vistas in high resolution non-destructive and non-invasive imaging of biological and soft structures under physiologically viable conditions. The ultrasound bioprobe will be positioned to provide abroad user base with exposure to the developed technology. Once developed, the technology will be accessible to other institutions, broadening their user base to include life sciences. In undergraduate course material, the PI?s will use examples from this research project to highlight how integration of engineering and physical principles is incorporated into real biological research. The PI?s will promote the active participation of women and other minorities in science and participation in classroom visits to elementary schools through the Science Chicago program in Midwest and Chicago public institutions for broader audience. The education plan focuses on development of a teaching module in sub-cellular imaging which includes hand-on-laboratory demo and classroom tutorials. The educational objectives will be achieved by (a) providing hand-on, team experience to promote active and collaborative learning; (b) exposing promising students at the undergraduate level to research opportunities in emerging field of sub-cellular biological imaging, and (c) to recruit and retain traditionally under-represented students though MIN (Minority Internships in Nanotechnology) programs which provide opportunities for undergraduates to participate in hands-on research in the area of nanotechnology.Thsi award is co-funded by CBET/Biophotonics Program, and Instrument Development for Biological Research (IDBR).