Fabrication of homogenous three‐dimensional biomimetic tissue for mass spectrometry imaging

Abstract

Reference samples are essential for mass spectrometric method optimization, data quality control, and target analyte quantitation. However, it is highly challenging to prepare an ideal homogeneous, standard‐spiked tissue sample for mass spectrometry imaging (MSI) research. Herein, we present a standard‐spiked 3D biomimetic tissue model fabricated with native cells, homogenate matrix, and biocompatible polymer. Unlike traditional homogenized tissue surrogates or those constructed with “on‐tissue” or “under‐tissue” micropipetting strategies, this simulated tissue shares both structural integrity of cells and homogeneous properties of matrix. As a result, analyte standards could undergo more in‐depth incorporation and has a more comparable native status with a real tissue. Series of tissue sections made from the 3D tissue model were proven to be feasible and useful for the parameter optimization, analyte quantitation, and calibration curve fitting for the air‐flow assisted desorption electrospray ionization MSI. Additionally, by analyzing the quality control model sections, we proposed a median principal component score calibration and demonstrated that this method can normalize instrumental fluctuations to stable levels in a large‐scale untargeted MSI experiments for the reliable metabolomic biomarker discovery. Thus, these results indicated that the standard‐spiked 3D biomimetic tissue has convincing significance in MSI analysis

X-dimensional Mass Spectrometry Imaging Discovers Spatially Resolved Metabolic Response

“…In this study, the AFADESI-MSI was introduced to implement spatial metabolomics data acquisition. After a decade of efforts in its hardware upgrading 29,30 , software development 40,41 , and methodology studies 42,43,44,45 , the detection sensitivity improvement has been remarkably achieved on this platform to widely cover various types of metabolites. In the drug's anti-tumor efficacy study, there were 869 target metabolites (1816 positive and negative ions) involved in 62 different types of metabolism pathways, species, and biotransformation in the metabolite ion library.…”

Cholesterol sulfate alleviates ulcerative colitis by promoting cholesterol biosynthesis in colonic epithelial cells

“…To guarantee the correction of the peak assignment above, the CID-MS/MS experiment was also conducted with the collision energy set at 15 V. Mouse colonic tissues were opened longitudinally, rolled into Swiss rolls and embedded in OCT. After thawing mounted on glass slides, tissue cryosections (10 μm) were fully dehydrated at room temperature before analysis. To compare the CS contents, a diluted series of CS standard-spiked simulative tissue was prepared to construct the quantitation curve according to previous reports 41 , 42 . After DESI-MSI data acquisition, Xcalibur (Thermo Scientific) was first employed for converting a batch of raw data files into cdf files.…”

Mass spectrometry imaging advances and application in pharmaceutical research

“…The tissue-specific ion suppression can be well-compensated by deuterated internal standards, chemometric calibration [54], or external evaluation of the tissue signal extinction coefficient [55]. A dilution series of drug and internal standards can be incorporated into a blank tissue to serve as the simulative dose one by several strategies, including the on dry tissue method (the most frequently used) [56], under wet tissue method [57], in-tissue homogenate [58], and in biomimetic 3D tissue [59]. Another alternative strategy is to introduce laser-capture microdissection (LCM) to harvest numerous tiny tissue regions of interest for follow-up LC-MS/ MS measurement [60,61].…”