Plasmonic Gold Nanoshell-Assisted Laser Desorption/Ionization Mass Spectrometry for Small-Biomolecule Analysis and Tissue Imaging

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 SiO 2 @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, SiO 2 @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 SiO 2 @Au nanoshells, the spatial distribution of various smallmolecule metabolites can be visualized in strawberry tissues at a pixel size of 100 μm without imaging artifacts. More valuably, the universality of SiO 2 @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 SiO 2 @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.

Integrated mass spectrometry imaging and metabolomics reveals sublethal effects of indoxacarb on the red fire ant Solenopsis invicta

“…Among them, the MS image of PE(36:1p) showed that it was distributed in the brain of S. invicta , whereas PE(38:5) mainly accumulated in the brain with a slight distribution in part of the abdomen. Additionally, PC(36:3) was located in part of the abdomen, whereas most TG species, such as TG(51:2) and TG(52:2), were found to accumulate throughout the whole‐body section of S. invicta , which is in agreement with previous reports 45,51 …”

“…Additionally, PC(36:3) was located in part of the abdomen, whereas most TG species, such as TG(51:2) and TG(52:2), were found to accumulate throughout the whole-body section of S. invicta, which is in agreement with previous reports. 45,51 3.5 Metabolic pathway analysis of S. invicta in response to indoxacarb The aforementioned metabolic results indicate that indoxacarb treatment could induce significant cross-regulation of metabolites. Thus, we determined the metabolism pathways of S. invicta in response to indoxacarb, including pentose and glucuronate interconversions, starch and sucrose metabolism, alanine, aspartate, and glutamate metabolism, and pyrimidine metabolism (Fig.…”

Carbon-Based Nanoparticles and Their Surface-Modified Counterparts as MALDI Matrices

“…205 A higher number of analytes were detected with lower matrix-related interferences, lower LODs, and better reproducibility of the results compared to the conventional matrix, CHCA. 205 The same "coating" concept was applied in carbon-based nanoparticles when CNTs were combined with polydopamine to enhance their water miscibility, as discussed above. 60 The surface of silica nanoparticles has also been modified with gold, platinum, silver, and palladium nanoparticles to enhance their performance as a matrix for the analysis of antidepressant medications.…”

“…The main constituent in the structures of these nanosized matrices can be a variety of particles, such as gold, silver, iron oxide, or titanium dioxide. − The main structural differences between metal nanoparticles and carbon-based ones are the high variability in the crystal structures of the metal-based nanoparticles compared to the more homogeneous structure of the carbon-based nanoparticles. Metal-based nanoparticles have been combined with other compounds to improve their physicochemical properties, increasing their efficiency as MALDI matrices. − Silica particles, for example, have been coated with gold nanoparticles and used as a matrix for MALDI imaging of a series of low molecular weight compounds, such as amino acids, peptides, and small carbohydrates in a variety of plant and animal tissues . A higher number of analytes were detected with lower matrix-related interferences, lower LODs, and better reproducibility of the results compared to the conventional matrix, CHCA .…”

“…Metal-based nanoparticles have been combined with other compounds to improve their physicochemical properties, increasing their efficiency as MALDI matrices. − Silica particles, for example, have been coated with gold nanoparticles and used as a matrix for MALDI imaging of a series of low molecular weight compounds, such as amino acids, peptides, and small carbohydrates in a variety of plant and animal tissues . A higher number of analytes were detected with lower matrix-related interferences, lower LODs, and better reproducibility of the results compared to the conventional matrix, CHCA . The same “coating” concept was applied in carbon-based nanoparticles when CNTs were combined with polydopamine to enhance their water miscibility, as discussed above .…”