Mapping Molecular Signatures in Plant Leaves, Flowers, and Fruits by a TiO₂ Nanotube-Based Plasmonic Chip for Imprint Mass Spectrometry Imaging

Abstract

Mapping molecular signatures within a fragile leaf or flower of medicinal plants with mass spectrometry imaging (MSI) techniques is crucial in plant biology yet remains a great challenge due to the inability to slice such samples. Herein, we constructed a composite substrate, hydrophobic polydopamine-modified TiO2 nanotube coated with plasmonic gold nanoparticle (AuNP-hPDA-TDNT) and exploited its potential as a surface-assisted laser desorption/ionization (SALDI) substrate for imprinting/stamping MSI analysis. With the integrated advantages of satisfactory imprinting/stamping capability and enhanced ion production, this AuNP-hPDA-TDNT substrate-based SALDI-MSI exhibits remarkable performance in mapping tissue-specific distribution patterns of functional metabolites in medicinal plant (i.e., Catharanthus roseus, Ginkgo biloba, and Jatropha integerrima) leaves/flowers and fruits (i.e., strawberry and cherry tomato) regardless of tedious sample preparation. Collectively, we believe that this functionalized TiO2 nanotube substrate will expand the scope of SALDI-MSI in plant science, providing more biologically relevant insights into the functions and mechanisms of plant systems.

Temporally and spatially resolved molecular profiling in fingerprint analysis using indium vanadate nanosheets-assisted laser desorption ionization mass spectrometry

“…In the last decades, multifarious nanomaterials (e.g. porous silicon [ 8 , 9 ], carbon-based materials [ 10 – 12 ], metal oxides [ 13 – 16 ], metal-organic frameworks [ 17 , 18 ], and metal nanomaterials [ 19 , 20 ]) several techniques have been developed for the fabrication of SALDI nano-matrices. The efficacy of these nano-matrices has been extensively demonstrated in several applications of SALDI-MS. For instance, Pleskunov et al reported niobium nanoparticles based SALDI-MS method for multiple phospholipids analysis on mouse brain tissue [ 21 ].…”

Thin‐section‐ and matrix‐free mass spectrometry imaging: Reproducible sample transfer using novel platinum‐coated porous plate formed of glass beads

“…One of the simplest approaches is a process in which a cross-section (not a thin section) of a sample is placed in contact with the prepared SALDI medium. For example, this method was used to obtain MSI results for a plant or kidney tissue transferred onto a silver-109 (or gold) nanoparticleenhanced target, 16,17 a strawberry transferred with desorption ionization using a through-hole alumina membrane, 18 and a plant tissue, such as a leaf, transferred on a gold nanoparticle-supported medium (a filter paper 19,20 or TiO 2 nanotubes 21 ). These approaches are effective in relieving the stress caused by preparation.…”