Ambient Molecular Analysis of Biological Tissue Using Low-Energy, Femtosecond Laser Vaporization and Nanospray Postionization Mass Spectrometry

Abstract

Abstract. Direct analysis of plant and animal tissue samples by laser electrospray mass spectrometry (LEMS) was investigated using low-energy, femtosecond duration laser vaporization at wavelengths of 800 and 1042 nm followed by nanospray postionization. Low-energy (<50 μJ), fiber-based 1042 nm LEMS (F-LEMS) allowed interrogation of the molecular species in fresh flower petal and leaf samples using 435 fs, 10 Hz bursts of 20 pulses from a Ytterbium-doped fiber laser and revealed comparable results to high energy (75-1120 μJ), 45 fs, 800 nm Ti:Sapphire-based LEMS (Ti:Sapphire-LEMS) measurements. Anthocyanins, sugars, and other metabolites were successfully detected and revealed the anticipated metabolite profile for the petal and leaf samples. Phospholipids, especially phosphatidylcholine, were identified from a fresh mouse brain section sample using Ti:Sapphire-LEMS without the application of matrix. These lipid features were suppressed in both the fiber-based and Ti:Sapphire-based LEMS measurements when the brain sample was prepared using the optimal cutting temperature compounds that are commonly used in animal tissue cryosections.

Classification of Gunshot Residue Using Laser Electrospray Mass Spectrometry and Offline Multivariate Statistical Analysis

“…LEMS has been used to detect and classify different types of explosives, such as inorganic salts, high explosives, and unburnt smokeless powders . Furthermore, LEMS analyses have been conducted on a variety of analytes including pharmaceuticals, lipids, narcotics, benzylpyridinium molecules, dipeptides, proteins, − plant, , and mammalian tissue suggesting LEMS would be amenable for GSR analysis.…”

Plant Single-Cell Metabolomics—Challenges and Perspectives

“…It is not accidental that the great majority of these studies focused on tissues that accumulate specialized metabolites in a large abundance and can be relatively easily accessed, such as glandular trichomes [62,[65][66][67], laticifers [60,68], and floral petals [69][70][71]. Indeed, as metabolites physiologically accumulate in these organs and structures, their concentration is already optimized to detect an MS signal of sufficient quality for the molecular identification of compounds.…”

Laser Desorption/Ablation Postionization Mass Spectrometry: Recent Progress in Bioanalytical Applications

“…Applications of LEMS in biological analysis have been focused on characterization of small metabolites and macro biomolecules including enzyme, proteins, and phosphorous lipids from human blood and egg white/yolk (Judge, Brady, & Levis, 2010); amphiphilic lipids and hydrophobic proteins deposited on steel and glass substrates (Brady, Judge, & Levis, 2011a); plant tissue typing using compressive linear classification (Judge et al, 2011); plant phenotype discrimination using multivariate statistical analysis (Flanigan et al, 2012); acid sensitive proteins with increased charge states when infusing supercharging reagents into the electrospray or deceasing the electrospray flow rate (Karki et al, 2015); folded proteins and hemoglobin α subunit‐heme complex from whole blood with LEMS integrating with a fiber‐based femtosecond laser at 1042 nm (Shi et al, 2015); and small metabolites from plant samples using the low pulse energy fiber‐based laser for analytes desorption, with comparable results to high energy Ti: Sapphire laser‐based LEMS measurements (Shi et al, 2016b).…”