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Three-dimensional electron microscopy imaging of medical materials

医用材料三维电子显微镜成像

基本信息

批准号：
BB/E007422/1
负责人：
Athene Donald DBE FRS
金额：
$ 46.7万
依托单位：
University of Cambridge
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FE007422%2F1
关键词：
Three dimensional electron microscopy imaging

项目摘要

Many samples of relevance to the medical materials industry are complex, containing mixed phases and interfaces buried within the sample. As an example one can consider what happens when a prosthetic device is implanted in an animal/human. The cells must stick to the device and spread and grow healthily. Studying the nature of this interface is therefore crucial, and it is important to find ways to image the three dimensional structure in its vicinity. Pills and tablets, as a means of delivering medicines, are another example. For these, the porosity of the tablet (which will depend on how the tablet was processed) and how the drug is distributed within the porous structure are key variables. The ability to image these structures at rather high magnifications, so that the detail of the structure is clear, is therefore crucial. Optical microscopy cannot always provide the level of detail required because of its limited resolution. However, conventional electron microscopy usually requires the use of high magnification and either ultra-thin samples (transmission electron microscopy) or only surface imaging can be performed (scanning electron microscopy). In this proposal we describe a new kind of electron microscopy which overcomes these problems, and opens up the way to build up three dimensional images of these complex medical materials. The technique uses a so-called Dual beam instrument, comprising both a conventional electron beam and also a focussed ion beam which can mill through materials. The ion beam cuts down through the material to expose buried interfaces. The electron beam, using a so-called environmental scanning electron microscope (ESEM) column, allows imaging of these exposed interfaces at high resolution. Because ESEM imagaing occurs in the presence of a low level of gas - and not an ultra high vacuum as in most scanning electron microscopes - insulators do not charge up under the electron beam. Thus the resolution is not degraded due to charging or the necessity of coating a sample with some conductive material. This approach will be developed for medical materials, both to develop appropriate protocols for this rather new approach, and also to solve specific problems to do with the porosity of tablets, and the nature of interfaces between spreading cells and an inorganic substrate.

与医疗材料行业相关的许多样品都很复杂，包含埋在样品中的混合相和界面。作为示例，可以考虑当假体装置植入动物/人中时会发生什么。细胞必须粘附在设备上，并健康地扩散和生长。因此，研究这个界面的性质是至关重要的，重要的是找到方法来成像其附近的三维结构。药丸和药片作为一种药物输送手段是另一个例子。对于这些，片剂的孔隙率（这将取决于片剂是如何加工的）和药物如何在多孔结构内分布是关键变量。因此，在相当高的放大倍数下对这些结构成像的能力是至关重要的，以便结构的细节是清晰的。光学显微镜由于其有限的分辨率而不能总是提供所需的细节水平。然而，传统的电子显微镜通常需要使用高放大倍数，并且可以进行超薄样品（透射电子显微镜）或仅表面成像（扫描电子显微镜）。在这个建议中，我们描述了一种新的电子显微镜，它克服了这些问题，并开辟了建立这些复杂的医学材料的三维图像的方式。该技术使用所谓的双束仪器，包括传统的电子束和聚焦的离子束，可以磨穿材料。离子束向下切穿材料以暴露掩埋的界面。使用所谓的环境扫描电子显微镜（ESEM）柱的电子束允许以高分辨率对这些暴露的界面进行成像。因为ESEM成像发生在低水平的气体存在下-而不是像大多数扫描电子显微镜那样的超高真空-绝缘体在电子束下不会充电。因此，分辨率不会由于充电或用一些导电材料涂覆样品的必要性而降低。这种方法将被开发用于医疗材料，既为这种相当新的方法开发适当的协议，也解决与片剂的孔隙率有关的具体问题，以及铺展细胞和无机基质之间的界面性质。