Nanoscopy for nanomedicine lab, Institute for Bioengineering of Catalonia, Baldiri Reixac, 08028, Barcelona, Spain.
Department School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, UK.
Chemistry. 2020 Aug 6;26(44):9869-9873. doi: 10.1002/chem.202001560. Epub 2020 Jun 18.
Self-assembly of fluorenylmethoxycarbonyl-protected diphenylalanine (FmocFF) in water is widely known to produce hydrogels. Typically, confocal microscopy is used to visualize such hydrogels under wet conditions, that is, without freezing or drying. However, key aspects of hydrogels like fiber diameter, network morphology and mesh size are sub-diffraction limited features and cannot be visualized effectively using this approach. In this work, we show that it is possible to image FmocFF hydrogels by Points Accumulation for Imaging in Nanoscale Topography (PAINT) in native conditions and without direct gel labelling. We demonstrate that the fiber network can be visualized with improved resolution (≈50 nm) both in 2D and 3D. Quantitative information is extracted such as mesh size and fiber diameter. This method can complement the existing characterization tools for hydrogels and provide useful information supporting the design of new materials.
芴甲氧羰基保护的二苯丙氨酸（FmocFF）在水中的自组装广泛用于制备水凝胶。通常，在湿条件下（即不冷冻或干燥）使用共聚焦显微镜来可视化此类水凝胶。然而，水凝胶的关键方面，如纤维直径、网络形态和网格尺寸，都是亚衍射限制的特征，无法通过这种方法有效地可视化。在这项工作中，我们证明了可以在不进行直接凝胶标记的情况下，通过点积累成像纳米形貌（PAINT）在天然条件下对 FmocFF 水凝胶进行成像。我们证明了纤维网络可以在 2D 和 3D 中以更高的分辨率（≈50nm）进行可视化。可以提取网格尺寸和纤维直径等定量信息。该方法可以补充现有的水凝胶表征工具，并提供支持新材料设计的有用信息。
