Cluster Ion Source for ESCA Instrument

描述（由申请人提供）：许多重要的细胞和组织功能依赖于分子的表面呈现，因此确定生物医学设备表面和近表面区域存在的生物部分的化学状态（组成，分子结构和取向）以及分布至关重要。因此，开发能够在高空间分辨率下提供定量和详细的表面化学状态信息的表面分析技术至关重要，无论是表面的二维成像还是近表面区域的三维成像。直到最近，化学分析电子能谱（ESCA，也称为x射线光电子能谱或XPS）还不可能通过溅射深度剖面获得生物材料的三维图像。这是因为ESCA仪器上可用的商业离子源产生单原子物种，如Ar+，导致样品在溅射过程中严重降解和分子信息丢失。几年前，像C60+这样的商业集群离子源在飞行时间二次离子质谱（ToF-SIMS）仪器上可用。这些资源能够对生物材料进行分子深度分析，并开启了使用ToF-SIMS进行三维成像的可能性。基于这些簇离子束源在ToF-SIMS社区中取得的成功，它们现在正在开发用于商用ESCA仪器。2008年秋天，我们在华盛顿大学（Kratos Analytical）的成像ESCA仪器的制造商为他们的AxisUltra DLD仪器引入了一个簇离子束源，现在使ESCA分子深度分析和生物材料的3-D成像成为可能。为了利用这些新功能以及它们将为nih资助的研究项目提供的好处，我们申请115,000美元，用新的集群离子束源升级我们现有的Kratos Analytical AxisUltra DLD ESCA仪器。ESCA和ToF-SIMS是互补的表面分析技术。ESCA提供元素和化学物种组成的定量信息，而ToF-SIMS提供更详细的分子结构信息。因此，结合ESCA和ToF-SIMS的三维成像提供了样品的详细定量和分子结构信息。将受益于新的3-D ESCA成像能力的研究项目包括分析医疗植入物（例如，载药/涂层支架）、生物膜、细胞片、组织切片、组织工程支架、微阵列设备（DNA、抗体、碳水化合物等）、生物传感器等。

DESCRIPTION (provided by applicant): Many important cell and tissue functions depend on the surface presentation of molecules, so it is critical to determine the chemical state (composition, molecular structure, and orientation) as well as the distribution of biological moieties present on a surface and in the near surface region of biomedical devices. Thus, it is essential to develop surface analysis techniques capable of providing quantitative and detailed surface chemical state information at high spatial resolutions, both for 2-D imaging of surfaces and 3-D imaging of the near surface region. Until recently it was not possible with electron spectroscopy for chemical analysis (ESCA, also known as x-ray photoelectron spectroscopy or XPS) to obtain 3-D images of biological materials by sputter depth profiling. This is because the commercial ion sources available on ESCA instruments produced monoatomic species such as Ar+ that resulted in significant sample degradation and loss of molecular information during sputtering. A few years ago commercial cluster ion sources such C60+ became available on time-of-flight secondary ion mass spectrometry (ToF-SIMS) instruments. These sources were capable of molecular depth profiling of biological materials and opened the possibility of 3-D imaging with ToF-SIMS. Building on the success these cluster ion beam sources have experienced in the ToF-SIMS community, they are now being developed for commercial ESCA instruments. In the Fall of 2008 the manufacturer of our imaging ESCA instrument at the University of Washington (Kratos Analytical) introduced a cluster ion beam source for their AxisUltra DLD instrument, which now makes ESCA molecular depth profiling and 3-D imaging of biological materials possible. To capitalize on these new capabilities and the benefits they will provide to NIH-funded research projects, we are requesting $115,000 to upgrade our existing Kratos Analytical AxisUltra DLD ESCA instrument with the new cluster ion beam source. ESCA and ToF-SIMS are complementary surface analysis techniques. ESCA provides quantitative information about elemental and chemical species composition, while ToF-SIMS provides more detailed molecular structure information. Thus, combined 3-D imaging with both ESCA and ToF-SIMS provide detailed quantitative and molecular structure information about a sample. Research projects that will benefit from the new 3-D ESCA imaging capability include analysis of medical implants (e.g., drug-loaded/coated stents), biofilms, cell sheets, tissue sections, tissue engineering scaffolds, microarray devices (DNA, antibody, carbohydrate, etc.), biosensors, etc. HEALTH RELEVANCE: Knowledge about biomedical implant surfaces and an understanding of how these surfaces interact and direct biological processes when such a device is placed in the body is needed to permit the rational design of new and improved biomedical implants. The proposed cluster ion beam source will provide new information about the surface properties of biomedical devices that is needed to achieve this objective.