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

在生物学领域，迫切和及时地需要创新和非侵入性的成像方法，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有效性。西北大学的这一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“超声生物探头”。本项目的目标是开发具有高次谐波能力的超声生物探头，以检测和跟踪生理条件下纳米级的亚细胞缺陷。预期的应用将研究细胞转染下内皮细胞的动力学，以开发早期治疗急性肺损伤的潜在疗法。它将进一步扩展到研究肿瘤细胞在发育开始时的进展。在超声生物探头中，悬臂梁监测表面声波的扰动，特别是它们的相位，这些扰动携带着由于样品声波各自粘弹性性质的不同而反映在样品声波散射中的嵌入或埋藏子结构的信息。由于亚表面纳米结构/缺陷的存在以及近表面的变化，体波的幅度和相位的变化会影响悬臂梁检测到的差频信号(节拍)的幅度和相位。这些变化用于创建由地下特征/缺陷和近地表特征/缺陷生成的空间映射。要实现这些努力，需要一种方法，将扫描探针显微镜硬件、功能电子学及其集成到一个FPGA(现场可编程门阵列)中，以便使用LabVIEW代码同时产生和检测扫描中的多个谐波。通过利用扫描探针显微镜的纳米级分辨率和高次谐波的使用，这种创新的方法可能提供一种新的方法来近实时地执行活细胞的亚细胞生物成像，而不受传统的电子显微镜方法中需要细胞化学固定或冷冻保存的挑战的限制，以及传统的需要荧光标记成像和具有微尺度分辨率的共聚焦/荧光显微镜。超声生物探针检测纳米级特征的能力对于研究携带质粒的人肺动脉内皮细胞的纳米力学具有重要意义。它将有助于理解如何调节内皮细胞的结构排列，从而导致肺血管的屏障功能特性，并帮助治疗靶点。该项目的广泛影响有望在生理上可行的条件下对生物和软结构进行高分辨率、非破坏性和非侵入性成像方面开辟新的前景。超声波生物探头将被定位为向广泛的用户群提供接触到所开发的技术的机会。一旦开发出来，其他机构将可以使用这项技术，从而扩大他们的用户基础，将生命科学包括在内。在本科课程材料中，皮？S将用这个研究项目中的例子来强调工程和物理原理的结合是如何融入到实际的生物学研究中的。派？S将通过中西部的科学芝加哥计划和芝加哥公共机构的更广泛的受众，促进妇女和其他少数族裔积极参与科学和对小学的课堂访问。教育计划的重点是开发亚细胞成像的教学模块，其中包括动手实验室演示和课堂教程。教育目标将通过(A)提供实践，团队经验，以促进积极和合作的学习；(B)使有前途的本科生接触新兴的亚细胞生物成像领域的研究机会，以及(C)通过MIN(纳米技术少数派实习)计划招收和留住传统上代表性不足的学生，该计划为本科生提供参与纳米技术领域实践研究的机会。该奖项由CBET/生物光子学计划和生物研究仪器开发(IDBR)共同资助。

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).