Department of Chemistry, University of Illinois, 600 South Mathews Ave.; 63-5, Urbana, IL 61801, USA.
J Am Soc Mass Spectrom. 2011 May;22(5):828-36. doi: 10.1007/s13361-011-0111-2. Epub 2011 Mar 26.
Mass spectrometry imaging (MSI) provides the ability to detect and identify a broad range of analytes and their spatial distributions from a variety of sample types, including tissue sections. Here we describe an approach for probing neuropeptides from sparse cell cultures using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MSI--at single cell spatial resolution-in both MS and tandem MS modes. Cultures of Aplysia californica neurons are grown on an array of glass beads embedded in a stretchable layer of Parafilm M. As the membrane is stretched, the beads/neurons are separated physically and the separated beads/neurons analyzed via MALDI TOF MS. Compared with direct MS imaging of samples, the stretching procedure enhances analyte extraction and incorporation into the MALDI matrix, with negligible analyte spread between separated beads. MALDI tandem MSI using the stretched imaging approach yields localization maps of both parent and fragment ions from Aplysia pedal peptide, thereby confirming peptide identification. This methodology represents a flexible platform for MSI investigation of a variety of cell cultures, including functioning neuronal networks.
质谱成像（MSI）能够从各种样本类型（包括组织切片）中检测和识别广泛的分析物及其空间分布。在这里，我们描述了一种使用基质辅助激光解吸/电离飞行时间（MALDI-TOF）MSI-在 MS 和串联 MS 模式下-以单细胞空间分辨率探测稀疏细胞培养物中神经肽的方法。加利福尼亚海兔神经元的培养物生长在嵌入可拉伸 Parafilm M 层中的玻璃珠阵列上。当膜拉伸时，珠子/神经元在物理上被分离，并且通过 MALDI TOF MS 分析分离的珠子/神经元。与直接对样品进行 MS 成像相比，拉伸过程增强了分析物的提取和掺入 MALDI 基质中，在分离的珠子之间几乎没有分析物扩散。使用拉伸成像方法的 MALDI 串联 MSI 产生了来自 Aplysia 足肽的母体和片段离子的定位图，从而确认了肽的鉴定。该方法代表了用于各种细胞培养物（包括功能性神经网络）的 MSI 研究的灵活平台。
