Department of Chemistry, George Washington University, Washington, DC, 20052, USA.
Divisions of Plant Sciences and Biochemistry, C. S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA.
Angew Chem Int Ed Engl. 2021 Apr 12;60(16):9071-9077. doi: 10.1002/anie.202015251. Epub 2021 Mar 9.
Mass spectrometry imaging (MSI) enables simultaneous spatial mapping for diverse molecules in biological tissues. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) has been a mainstream MSI method for a wide range of biomolecules. However, MALDI-MSI of biological homopolymers used for energy storage and molecular feedstock is limited by, e.g., preferential ionization for certain molecular classes. Matrix-free nanophotonic ionization from silicon nanopost arrays (NAPAs) is an emerging laser desorption ionization (LDI) platform with ultra-trace sensitivity and molecular imaging capabilities. Here, we show complementary analysis and MSI of polyhydroxybutyric acid (PHB), polyglutamic acid (PGA), and polysaccharide oligomers in soybean root nodule sections by NAPA-LDI and MALDI. For PHB, number and weight average molar mass, polydispersity, and oligomer size distributions across the tissue section and in regions of interest were characterized by NAPA-LDI-MSI.
质谱成像（MSI）能够同时对生物组织中的多种分子进行空间映射。基质辅助激光解吸电离（MALDI）质谱（MS）是一种广泛用于各种生物分子的主流 MSI 方法。然而，用于储能和分子原料的生物均聚物的 MALDI-MSI 受到例如某些分子类别优先电离的限制。硅纳米柱阵列（NAPAs）的无基质纳米光子电离（nanophotonic ionization）是一种新兴的激光解吸电离（LDI）平台，具有超痕量灵敏度和分子成像能力。在这里，我们展示了通过 NAPA-LDI 和 MALDI 对大豆根瘤切片中的聚羟基丁酸（PHB）、聚谷氨酸（PGA）和多糖低聚物进行互补分析和 MSI。对于 PHB，通过 NAPA-LDI-MSI 对整个组织切片以及感兴趣区域中的数均和重均摩尔质量、分散度以及低聚物的尺寸分布进行了表征。
