Cluster Ion Source for ESCA Instrument

描述(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中存在的生物部分的化学状态(组成、分子结构和取向)以及分布是至关重要的。因此，必须开发能够以高空间分辨率提供定量和详细的表面化学状态信息的表面分析技术，既用于表面的二维成像，也用于近表面区域的三维成像。直到最近，用于化学分析的电子能谱(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析获得生物材料的三维图像。这是因为ESCA仪器上的商用离子源产生的单原子物种，如Ar+，在溅射过程中导致样品严重退化和分子信息丢失。几年前，C60+等商业团簇离子源在飞行时间二次离子质谱仪(ToF-SIMS)上出现。这些来源能够对生物材料进行分子深度剖析，并为使用ToF-SIMS进行三维成像打开了可能性。在这些团簇离子束源在TOF-SIMS社区取得成功的基础上，它们现在正被开发用于商用ESCA仪器。2008年秋天，我们的成像ESCA仪器制造商华盛顿大学(Kratos Analytical)为他们的AxisUltra DLD仪器引入了一种簇状离子束源，现在它使ESCA分子深度剖析和生物材料的3D成像成为可能。为了充分利用这些新能力以及它们将为美国国立卫生研究院资助的研究项目带来的好处，我们申请了115,000美元，用于将我们现有的Kratos Analytical AxisUltra DLD ESCA仪器升级为新的团簇离子束源。ESCA和ToF-SIMS是互补的表面分析技术。ESCA提供有关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3-D成像提供了关于样品的详细的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。 健康相关性：需要了解生物医学植入物表面的知识，并了解这些表面如何相互作用，以及当这样的装置被放置在体内时如何指导生物过程，以允许合理设计新的和改进的生物医学植入物。建议的团簇离子束源将提供有关实现这一目标所需的生物医学设备表面属性的新信息。

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.