Center for Nano-Bio Measurement, Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, South Korea.
Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, South Korea.
Biointerphases. 2020 Apr 14;15(2):021011. doi: 10.1116/6.0000105.
Since Ar-gas cluster ion beams (Ar-GCIBs) have been introduced into time-of-flight secondary ion mass spectrometry (ToF-SIMS), there have been various attempts to analyze organic materials and biomolecules that require low-damage analysis and high sensitivity, because Ar-GCIBs allow soft ionization of large molecules such as peptides and proteins due to the low energy per atom. Here, the authors adopted the Ar-GCIB as a primary beam to detect proteins including human insulin, ubiquitin, and cytochrome C (molecular weights are 5808, 8564, and 12 327 Da, respectively). They have confirmed that the detection of the intact proteins was possible when the Ar-GCIB was used as a primary ion beam. In addition, they successfully identified each protein by analyzing the trypsin-digested peptides in myoglobin, cytochrome C, and bovine serum albumin. They also attempted on-surface enzymatic digestion to identify proteins on the surface of the Si wafer and obtained results identical to those of in-solution digestion. It is expected that the authors' on-surface digestion method can enable the application of ToF-SIMS for the analysis of proteins present in biological tissues.
自从氩气团簇离子束（Ar-GCIB）被引入飞行时间二次离子质谱（ToF-SIMS）以来，人们一直试图分析需要低损伤分析和高灵敏度的有机材料和生物分子，因为氩气团簇离子束由于每个原子的能量低，可以使肽和蛋白质等大分子软电离。在这里，作者采用 Ar-GCIB 作为初级束来检测包括人胰岛素、泛素和细胞色素 C（分子量分别为 5808、8564 和 12327Da）在内的蛋白质。他们已经证实，当使用 Ar-GCIB 作为初级离子束时，可以检测到完整的蛋白质。此外，他们通过分析肌红蛋白、细胞色素 C 和牛血清白蛋白中的胰蛋白酶消化肽成功地鉴定了每种蛋白质。他们还尝试了表面酶解，以鉴定 Si 晶片表面的蛋白质，并获得了与溶液内酶解相同的结果。预计作者的表面酶解方法可以使 ToF-SIMS 应用于分析生物组织中存在的蛋白质。
