Mello Monique G, Lockwood Thomas E, Wanagat Jonathan, Westerhausen Mika T, Bishop David P
Hyphenated Mass Spectrometry Laboratory, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, NSW 2007, Australia.
Division of Geriatrics, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
J Anal At Spectrom. 2024 Jul 1;39(7):1720-1725. doi: 10.1039/D3JA00467H. Epub 2024 May 29.
Elemental bioimaging of low abundant elements via laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) is hampered by a lack of sensitivity. Novel solutions for specific applications have been developed, however there is a need for more universal approaches. Here we investigated the addition of N to the ICP carrier gas to increase sensitivity, defined as signal-to-background, for the majority of biologically relevant elements. A gelatine standard that contained 38 elements across the mass range was ablated with increasing amounts of N added to the carrier gas post-ablation. The results show that while all elements examined had an increase in signal intensity, some elements did not have a resultant increase in signal-to-background. Sc, V, Mn, Fe, and Se all exhibited a reduction in signal-to-background ratios across all N flow rates examined, with the remaining elements experiencing signal-to-background increases from 1.2-7.8x, depending on the N flow rate and element. A compromised optimum N flow rate was determined for the analysis all elements and used to image endogenous elements in a mouse brain, and antibody-conjugated elements in a quadriceps muscle section. These images confirmed that the addition of N2 to the carrier gas increased the signal-to-background of the analysis, improving image resolution for endogenous elements and low abundant analytes used for immuno-mass spectrometry imaging of biomarkers. These findings offer a promising avenue for advancing the capabilities of LA-ICP-MS in bio-imaging applications.
通过激光烧蚀-电感耦合等离子体质谱法（LA-ICP-MS）对低丰度元素进行元素生物成像受到灵敏度不足的阻碍。针对特定应用已经开发出了新的解决方案，然而仍需要更通用的方法。在此，我们研究了向电感耦合等离子体（ICP）载气中添加氮气以提高大多数生物相关元素的灵敏度（定义为信号与背景之比）。使用一种在整个质量范围内包含38种元素的明胶标准品进行烧蚀，在烧蚀后向载气中添加越来越多的氮气。结果表明，虽然所有检测的元素信号强度均有所增加，但有些元素的信号与背景之比并未随之增加。在所有检测的氮气流量下，钪、钒、锰、铁和硒的信号与背景比均降低，其余元素的信号与背景比则根据氮气流量和元素的不同增加了1.2至7.8倍。确定了一个适用于所有元素分析的折衷最佳氮气流量，并用于对小鼠大脑中的内源性元素以及股四头肌切片中的抗体偶联元素进行成像。这些图像证实，向载气中添加氮气可提高分析的信号与背景比，改善内源性元素和用于生物标志物免疫质谱成像的低丰度分析物的图像分辨率。这些发现为提升LA-ICP-MS在生物成像应用中的能力提供了一条有前景的途径。
