Nanoparticle-assisted laser desorption/ionization using sinapic acid-modified iron oxide nanoparticles for mass spectrometry analysis

Abstract

Iron oxide-based nanoparticles (NP) were covalently modified with sinapic acid (SA) through a condensation reaction to assist the ionization of both large and small molecules. The morphology of SA-modified NPs (SA-NP) was characterized by transmission electron microscopy (TEM), and the modification of the NP surface with SA was confirmed using ultraviolet (UV) and infrared (IR) spectroscopy. The number of SA molecules was estimated to be 6 per NP. SA-NP-assisted laser desorption/ionization was carried out on small molecules, such as pesticides and plant hormones, and large molecules, such as peptides and proteins. A peptide fragment from degraded proteins was detected more efficiently compared with conventional methods.

Gold nanoparticles for enhanced ionization and fragmentation of biomolecules using LDI‐MS

“…28 Most research on alternative matrix materials has focused on ionization of intact biomolecules, specifically peptides, with little attention to any fragmentation products. 4,5,22,[29][30][31] This work expands on previous biomolecule studies 4,32 and introduces carbohydrates, steroids, bile acids, and other small molecules as a focus.…”

“…Research using gold NPs for LDI‐MS determined an inverted NP‐to‐analyte ratio compared with traditional MALDI, as well as other distinct advantages for ionization, including (1) less chemical noise and secondary ion formation in the low mass region from the matrix, (2) flexible analyte solution preparation conditions, including tolerances for salts, surfactants, and pH, (3) the ability to tailor NP surface chemistry with adsorbed species, and (4) interesting analyte energetics resulting in unique fragmentation . Most research on alternative matrix materials has focused on ionization of intact biomolecules, specifically peptides, with little attention to any fragmentation products . This work expands on previous biomolecule studies and introduces carbohydrates, steroids, bile acids, and other small molecules as a focus.…”

“…Since the advent of matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), multiple means to promote analyte ionization have appeared in the literature, starting with the small organic acids from Karas and Hillenkamp, 1 and the ultrafine cobalt suspended in glycerol from Tanaka et al 2 Recently, a focus on materials that do not provide a true matrix for analytes, such as nanoparticles (NPs), have been of interest. 3 This has included gold, 4-7 silver, [8][9][10][11][12][13][14] carbonbased substrates, [15][16][17][18][19][20][21] iron-based NPs, 22,23 inorganic particles/ matrix, 23,24 and silicon surfaces. [25][26][27] Research using gold NPs for LDI-MS determined an inverted NP-to-analyte ratio compared with traditional MALDI, as well as other distinct advantages for ionization, including (1) less chemical noise and secondary ion formation in the low mass region from the matrix, (2) flexible analyte solution preparation conditions, including tolerances for salts, surfactants, and pH, (3) the ability to tailor NP surface chemistry with adsorbed species, and (4) interesting analyte energetics resulting in unique fragmentation.…”

Mechanisms of Nanophase-Induced Desorption in LDI-MS. A Short Review

“…In fact, such coatings can facilitate energy dissipation, thus promoting “softer” ionization [61,79,84,85], or can assist analyte ionization when a conventional matrix is covalently attached to NP surface [35,93]. Moreover, specific modification of NPs can lead to enrichment and selective detection [94,95,96,97,98], as in the case of aptamer-modified gold nanofilms applied to the analysis of circulating tumor cells [99].…”

“…However, this classification is somewhat limiting since, for instance, pure carbon can behave as an insulator, a semiconductor or a metal depending on its structure or atomic arrangement. Further, recently explored hybrid systems such as gold nanoparticles (AuNPs) supported on silicon plate with cationic copolymer [34], iron oxide nanoparticles modified with sinapic acid [35] or magnetic NPs coupled to TiO 2 [36], SiNWs functionalized by Ag nanoparticles [37,38], would not be included as well. Lately, Yonezawa et al [39] divided SALDI-MS techniques into two categories: (i) nanostructured surfaces such as commercially available DIOS, NALDI, Quickmass, and (ii) nanoparticle systems including diverse inorganic nanoparticles or combination of them.…”