Joignant Alena N, Hector Emily C, Barnes Morgan M, Kullman Seth W, Muddiman David C
FTMS Laboratory for Human Health Research, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA.
Department of Statistics, North Carolina State University, Raleigh, NC, 27695, USA.
Anal Bioanal Chem. 2025 Jan;417(1):83-93. doi: 10.1007/s00216-024-05653-7. Epub 2024 Nov 13.
Quantitative mass spectrometry imaging (qMSI) provides the relative or absolute analyte quantities in a biological specimen in a spatially resolved manner. However, the chemical complexity and physical structure of biological specimens often require one to precisely account for matrix effects in qMSI platforms. Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) completely ablates a volume of cryosectioned tissue. This enables the use of a normalization standard that is sprayed underneath the tissue for qMSI applications. Complete sampling has shown to be a significant advantage for qMSI by IR-MALDESI; however, the impact of high tissue heterogeneity has not been systematically studied or quantified. The bias introduced by tissue heterogeneity was investigated by uniformly spraying standards beneath and on top of a whole-body zebrafish section. The quantitative relationship between the signals of the two standards was investigated across this multi-organ model to serve future qMSI experiments by IR-MALDESI and other laser ablation-based sampling methods. The overall ratio between the standards sprayed on top of and beneath the tissue sections remained constant across the entire whole-body section despite significant tissue heterogeneity (e.g., gills, heart, and liver). Additionally, we noted that thinner and/or sucrose-embedded tissues improved these ratios, which will inform future qMSI investigations.
定量质谱成像（qMSI）能够以空间分辨的方式提供生物样本中分析物的相对或绝对含量。然而，生物样本的化学复杂性和物理结构常常要求人们在qMSI平台中精确考虑基质效应。红外基质辅助激光解吸电喷雾电离（IR-MALDESI）可完全消融一定体积的冷冻切片组织。这使得在qMSI应用中能够使用在组织下方喷洒的归一化标准物。对于IR-MALDESI的qMSI而言，完全采样已被证明是一个显著优势；然而，高组织异质性的影响尚未得到系统研究或量化。通过在整条斑马鱼切片的下方和上方均匀喷洒标准物，研究了组织异质性引入的偏差。在这个多器官模型中研究了两种标准物信号之间的定量关系，以便为未来基于IR-MALDESI和其他基于激光烧蚀的采样方法的qMSI实验提供参考。尽管存在显著的组织异质性（如鳃、心脏和肝脏），但在整个身体切片上，喷洒在组织切片上方和下方的标准物的总体比例保持恒定。此外，我们注意到更薄和/或蔗糖包埋的组织改善了这些比例，这将为未来的qMSI研究提供参考。
