Muko Daiki, Ikenaga Takanori, Kasai Masanori, Rabor Janice B, Nishitani Atsushi, Niidome Yasuro
Department of Chemistry and Bioscience, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Japan.
Division of Gene Research, Research Support Centre, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Japan.
J Mass Spectrom. 2019 Jan;54(1):1-6. doi: 10.1002/jms.4290.
For analysis of low abundance peptides in a tissue section, immunohistochemical staining through antibody-antigen interaction is a usual technique. The antibody is conjugated with a probe moiety that aids in highly sensitive detection. Gold nanoparticles, which show excellent chemical stability and variation of surface modifications, are expected to act as a sensitive mass probe to desorb gold ions (Au , Au , Au ) that are distinguishable from fragment ions from organic molecules. Here, green fluorescent proteins (GFP) in a tissue section of a transgenic zebrafish were detected by the gold mass probe conjugated with antibodies. Due to the efficient ionization and desorption of gold ions, imaging mass spectrometry of Au ions indicated the distribution of gold nanoparticles stained in a tissue section, and the mass signal distribution was consistent with the area where the GFP-expressing cells were distributed. Conventional immunofluorescence techniques showed intense autofluorescence that come from intrinsic fluorophores in the tissue section. In contrast, the gold nanoparticles acted as an immunostaining mass probe that displayed significantly lower background signals.
对于组织切片中低丰度肽段的分析，通过抗体 - 抗原相互作用进行免疫组织化学染色是一种常用技术。抗体与有助于高灵敏度检测的探针部分偶联。金纳米颗粒具有出色的化学稳定性和表面修饰的多样性，有望作为一种灵敏的质量探针来解吸与有机分子碎片离子可区分的金离子（Au⁺、Au²⁺、Au³⁺）。在此，通过与抗体偶联的金质量探针检测了转基因斑马鱼组织切片中的绿色荧光蛋白（GFP）。由于金离子的有效电离和解吸，Au³⁺离子的成像质谱表明了组织切片中染色的金纳米颗粒的分布，并且质量信号分布与表达GFP的细胞分布区域一致。传统免疫荧光技术显示出强烈的自发荧光，其来自组织切片中的固有荧光团。相比之下，金纳米颗粒作为一种免疫染色质量探针，显示出明显更低的背景信号。
