Inorganic Matrices Assisted Laser Desorption/Ionization Mass Spectrometry for Metabolic Analysis in Biofluids

Abstract

Metabolic analysis in biofluids interprets the end products in the bioprocess, emerging as an irreplaceable disease diagnosis and monitoring platform. Laser desorption/ionization mass spectrometry (LDI MS)‐based metabolic analysis holds great potential for clinical applications in terms of high throughput, rapid signal readout, and minimal sample preparation. There are two essential elements to construct the LDI MS‐based metabolic analysis: 1) well‐designed nanomaterials as matrices; 2) machine learning algorithms for data analysis. This review highlights the development of various inorganic matrices to comprehend the advantages of LDI MS in metabolite detection and the recent diagnostic applications based on target metabolite detection and untargeted metabolic fingerprints in biological fluids.

Construction of a ternary component chip with enhanced desorption efficiency for laser desorption/ionization mass spectrometry based metabolic fingerprinting

“…Mass spectrometry (MS) with high throughput, sensitivity, and accuracy has been recognized as a new tool for metabolite analysis (Griffiths et al, 2010;Stolee et al, 2012;Zenobi, 2013;Wang et al, 2022). Among the ever-developing MS technologies, laser desorption/ionization mass spectrometry (LDI MS) has attracted intense attention in the field of metabolic diagnosis, considering its microliter sample requirements and second-level detection speed (Huang et al, 2017;Li et al, 2021;Ding et al, 2022;Shu et al, 2022). Metabolites are mixed with UV-absorbing materials called a matrix, and the UV laser irradiation of the mixtures promotes the efficient desorption and soft ionization of the metabolites (Wu et al, 2016;Wu et al, 2017;Pei and Wan, 2020;Wang et al, 2020;Yang et al, 2020).…”

In Vitro Diagnostic Examination and Prognosis Surveillance by Hierarchical Heterojunction-Assisted Metabolic Analysis

“…Moreover, noble metals are capable of improving LDI efficiency because of their surface plasma resonance effect that can generate large densities of hot electrons under excitation conditions, which is beneficial to improve the adsorption and desorption of metabolites. 18,19 Drawing inspiration from the above-mentioned studies, it is very much possible that the transfer and separation efficiency of electron−hole pairs can be improved by adjusting the number and type of interfaces. The metal oxide p−n junction consisting of p-and n-type semiconductors has been regarded as an effective structure for charge trapping and separation, since the heterojunction can form a built-in electric field at the two-phase interface to hinder the recombination of electron−hole pairs.…”

“…As is well known, the matrix interface is the location that realizes generation, separation, transfer, and recombination of electron–hole pairs, while the recombination rate on the unitary interface is normally faster than trapping and transfer rates. , In this regard, researchers made much effort on the fabrication of binary matrices, such as polymer@Ag and COF-V@Au, with the purpose of applying noble metal nanoparticles as electron sinks to reduce the recombination rate. Moreover, noble metals are capable of improving LDI efficiency because of their surface plasma resonance effect that can generate large densities of hot electrons under excitation conditions, which is beneficial to improve the adsorption and desorption of metabolites. , Drawing inspiration from the above-mentioned studies, it is very much possible that the transfer and separation efficiency of electron–hole pairs can be improved by adjusting the number and type of interfaces. The metal oxide p–n junction consisting of p - and n -type semiconductors has been regarded as an effective structure for charge trapping and separation, since the heterojunction can form a built-in electric field at the two-phase interface to hinder the recombination of electron–hole pairs. , Generally, the built-in electric field will lead p-zone electrons to go through the p–n junction into the n-zone and n-zone holes to go into the p-zone when excited by the appropriate light source. , Furthermore, the high thermal capacity, high photothermal conversion, and low thermal conductivity of matrix materials favor photoionization and thermally driven desorption during LDI-MS, which can reduce thermal dissipation from materials themselves to the target plate and facilitate high-efficiency desorption of the analytes.…”

A Copper-Based Biosensor for Dual-Mode Glucose Detection

“…Nevertheless, it is a challenge to quantitatively analyze small molecules due to the background signal and coffee effect of traditional organic matrices ( Wu et al, 2018 ). In recent years, plenty of research has been paid more attention to nanomaterials-assisted LDI MS for metabolic analysis ( Cao et al, 2020 ; Liu et al, 2020 ; Ding et al, 2022 ). In the process of LDI MS, the matrix can uniformly distribute among the targets ( Dai et al, 2020 ) and enhance the ionization efficiency, largely improving the MS quantitative performance ( Kim et al, 2021 ).…”

“…LDI MS presents high sensitivity, accuracy, resolution, and throughput in molecular analysis, especially for metabolites at the low molecular weight ( Kulkarni et al, 2021 ). However, the efficiency of LDI MS relies on the matrix materials with designed molecular interfaces due to the size-exclusive effect and specific affinity ( Ding et al, 2022 ). In this work, the optimized Cu 2 O NPs could not only be used as peroxidase mimic but also be employed as the matrix for LDI MS analysis.…”