Effects of Silane Monolayers on Lysophosphatidylcholine (LysoPC) Detection by Desorption Ionization on Silicon Mass Spectrometry (DIOS-MS) in Solution and Plasma

Abstract

Desorption ionization on silicon mass spectrometry (DIOS-MS) enables high throughput analysis of low-molecular-weight biomolecules. However, detection of metabolite biomarkers in complex fluids such as plasma requires sample pretreatment, limiting clinical application. Here, we show that porous silicon, chemically modified using monolayers of n-propyldimethyl­methoxysilane molecules, is a good candidate for fingerprinting lysophosphatidyl­choline (lysoPC) in plasma, without sample pretreatment, for DIOS-MS-based diagnosis (e.g., sepsis). Results were correlated to lysoPC molecule location inside/outside the pores, determined by time-of-flight secondary ion mass spectrometry profiling, and to physicochemical properties.

Effect of Silane Monolayers and Nanoporous Silicon Surfaces on the Matrix-Assisted Laser Desorption Ionization Mass Spectrometry Detection of Sepsis Metabolites Biomarkers Mixed in Solution

“…In addition, to further increase the number of metabolites detected among the 25 metabolites studied, and also to further improve the limit of detection, DIOS-MS strategy, based on silanized porous silicon substrates, could be investigated. 47 Indeed, for instance, a slight CHCA matrix peak interferes with the [M + H] + peak of LysoPC, limiting its detection to around 0.5 ng/mL in the mix of metabolites studied. However, the physiological concentration of LysoPC is far above this detection limit, around 40 ng/mL, and decreases in the case of sepsis.…”

“…Then, a reduced number of substrates could be selected to improve the MALDI-ToF MS detection of the panel of sepsis metabolites. In addition, to further increase the number of metabolites detected among the 25 metabolites studied, and also to further improve the limit of detection, DIOS-MS strategy, based on silanized porous silicon substrates, could be investigated . Indeed, for instance, a slight CHCA matrix peak interferes with the [M + H] + peak of LysoPC, limiting its detection to around 0.5 ng/mL in the mix of metabolites studied.…”