Nanostructure-Dependent Signal Intensity in Through-Hole Porous Alumina Membranes for Mass Spectrometry Imaging

IF 1.7 3区化学 Q4 BIOCHEMICAL RESEARCH METHODS

Rapid Communications in Mass Spectrometry Pub Date : 2025-09-30 DOI:10.1002/rcm.10149

Masahiro Kotani, Takashi Yanagishita

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引用次数: 0

Abstract

Rationale

Matrix-assisted laser desorption/ionization (MALDI) is a widely used analytical technique for measuring high-molecular-weight compounds such as proteins. However, in the low-molecular-weight region, interference peaks derived from the matrix occur. Surface-assisted laser desorption/ionization (SALDI), which is matrix-free, does not generate background noise in the low-molecular-weight region and has the advantages of simple sample preparation and reproducibility. We previously developed an ionization method using an anodic porous alumina membrane (APAM) as a SALDI substrate. In this study, we examined the effects of the surface nanostructural properties of APAMs, such as hole diameter and pitch, on the signal intensity in mass spectrometry (MS) imaging.

Methods

APAMs were fabricated using electrolytes of oxalic, malonic, and malic acids and were evaluated by MS using droplet samples and MS imaging. Droplet samples were applied to the back surface of the APAMs. MS imaging was conducted using 20-μm-thick mouse brain sections to compare the signal-to-noise ratio (SNR) of each APAM.

Results

APAMs were fabricated with hole diameters (D_h) of 24–419 nm, interhole distances (D_int) of 100–625 nm, and open area ratios (OAR) of 5%–46%. From MS and MS imaging results, signal intensity at the same OAR increased in the order of D_int = 100, 625, and 270 nm, and the condition D_h/D_int = 131/270 nm provided the highest SNR. In addition, APAMs with a D_h of less than 84 nm and an OAR lower than 10% exhibited lower signal intensities.

Conclusions

We fabricated APAMs under various conditions and identified the processing conditions that provided the highest SNR of SALDI imaging. SALDI imaging using the APAMs fabricated under these high SNR conditions is expected to be applicable in various fields such as materials science and metabolomics, as it does not generate interference peaks in the low-molecular-weight region.

Abstract Image

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纳米结构依赖的信号强度在多孔氧化铝膜质谱成像

基质辅助激光解吸/电离（MALDI）是一种广泛应用于测量高分子量化合物（如蛋白质）的分析技术。然而，在低分子量区域，会出现来自基质的干涉峰。表面辅助激光解吸/电离（SALDI）是一种无基体的激光解吸/电离技术，在低分子量区域不会产生背景噪声，具有样品制备简单、重复性好等优点。我们之前开发了一种使用阳极多孔氧化铝膜（APAM）作为SALDI衬底的电离方法。在这项研究中，我们研究了APAMs表面纳米结构特性，如孔直径和节距，对质谱成像信号强度的影响。方法以草酸、丙二酸和苹果酸为电解液制备APAMs，采用液滴样品和质谱成像对APAMs进行鉴定。液滴样品被施加到apam的背面。采用20 μm厚的小鼠脑切片进行MS成像，比较各APAM的信噪比。结果制备的APAMs孔直径（Dh）为24 ~ 419 nm，孔间距（Dint）为100 ~ 625 nm，开孔率（OAR）为5% ~ 46%。从MS和MS成像结果来看，同一声腔处的信号强度按Dint = 100、625、270 nm依次增大，其中Dh/Dint = 131/270 nm时信噪比最高。此外，当偏h小于84 nm，桨距小于10%时，apam的信号强度较低。结论制备了不同条件下的apam，并确定了SALDI成像信噪比最高的处理条件。使用在这些高信噪比条件下制造的apam进行SALDI成像，预计将适用于材料科学和代谢组学等各个领域，因为它不会在低分子量区域产生干扰峰。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Rapid Communications in Mass Spectrometry 化学-分析化学

CiteScore

4.10

自引率

5.00%

发文量

219

审稿时长

2.6 months

期刊介绍： Rapid Communications in Mass Spectrometry is a journal whose aim is the rapid publication of original research results and ideas on all aspects of the science of gas-phase ions; it covers all the associated scientific disciplines. There is no formal limit on paper length ("rapid" is not synonymous with "brief"), but papers should be of a length that is commensurate with the importance and complexity of the results being reported. Contributions may be theoretical or practical in nature; they may deal with methods, techniques and applications, or with the interpretation of results; they may cover any area in science that depends directly on measurements made upon gaseous ions or that is associated with such measurements.