Plasmonic Gold Nanoshell-Assisted Laser Desorption/Ionization Mass Spectrometry for Small-Biomolecule Analysis and Tissue Imaging
Mingyi Du, Dong Chen, Yingying Chen, Yudi Huang, Lianlian Ma, Qingrong Xie, Yizhu Xu, Xinhai Zhu, Zilong Chen, Zhibin Yin, Hanhong Xu, Xinzhou Wu
Abstract
Plasmonic nanoshells have been acknowledged as efficient nanomaterials for laser desorption/ionization mass spectrometry (LDI-MS) detection of a wide range of small molecules, whereas their applications in mass spectrometry imaging (MSI) are less developed. In this work, we constructed and optimized SiO2@Au nanoshells with tailor-made shell structures and compositions for high-sensitivity LDI-MS analysis and a wide range of MSI applications. Owing to the synergistic effects of plasmonic shells with nanoscale roughness and specific crevice space for the selective trapping of small molecules and cations, SiO2@Au core–shell nanoparticles exhibit superior performance for the detection of a vast diversity of small molecules, including amino acids, oligosaccharides, dyestuff and drugs, peptides, nucleosides, and poly(ethylene glycols). Compared with organic matrices, this method affords a high reduction in matrix interference, higher analyte coverage, lower detection limits ranging from fmol to pmol, and good repeatability with relative standard deviation (RSD) below 5%. Due to the nanoscale size and homogeneous deposition of SiO2@Au nanoshells, the spatial distribution of various small-molecule metabolites can be visualized in strawberry tissues at a pixel size of 100 μm without imaging artifacts. More valuably, the universality of SiO2@Au-assisted LDI-MSI is further demonstrated for mapping the lipid distribution within the whole-body tissues of zebrafish (Danio rerio), honeybees (Apis cerana), and mouse brain tissues in a spatially resolved manner at pixel sizes of 55, 30, and 50 μm, respectively. These results facilitate the expansion of the abilities of plasmonic core–shell nanoparticles in real-case MSI applications. Taken together, the results indicate that the SiO2@Au nanoshells are expected to be promising and efficient nanomaterials with superior DI efficiency and imaging capabilities, especially in the environmental science and life science fields.