We present here a technology to microencapsulate drugs by the sol-gel process, and cryo-SEM methodology that allows the nanostructural characterization of the formed capsules in their native state without any artifacts, related to their drying prior to imaging. The methodology utilizes three signals generated by the electron beam scanning the specimen: Secondary electrons, backscattered electrons, and x-rays. The first gives topographical information of the fracture-surface of the thermally-fixed specimen, the second gives contrast between elements of different atomic numbers, and the third allows the identification of those elements. Combined, the three signals provide full microstructural characterization of the studied specimen.

Using this methodology, we were able to demonstrate that the sol-gel technology does indeed enable the encapsulation of two hydrophobic active molecules with a silica shell. This technology allows the active ingredient in the drug product to slowly migrate from the microcapsule onto the skin, thus obtaining the desired effect with minimal side-effects, as was exhibited in several clinical studies.

The successful application of the cryo-SEM methodology in this case, demonstrates that it can be used to characterize a wide range of liquid-phase suspensions, in their native state, with minimal specimen preparation or imaging artifacts.

我们在这里提出一种通过溶胶-凝胶工艺微囊化药物的技术，以及低温SEM方法，该技术可以使形成的胶囊在其原始状态下进行纳米结构表征，而没有任何伪影，这与成像前的干燥有关。该方法利用电子束扫描样品产生的三个信号：二次电子，反向散射电子和X射线。第一个给出热固定试样断裂表面的形貌信息，第二个给出不同原子序数元素之间的对比，第三个给出识别这些元素的方法。结合在一起，这三个信号提供了所研究标本的完整微观结构特征。

使用这种方法，我们能够证明溶胶-凝胶技术确实能够使两个疏水性活性分子与二氧化硅壳一起包封。这项技术使药物产品中的活性成分能够从微胶囊缓慢迁移到皮肤上，从而以最小的副作用获得所需的效果，如多项临床研究所示。

在这种情况下，cryo-SEM方法的成功应用表明，它可用于以其自然状态，最少的样品制备或成像伪像来表征各种液相悬浮液。