On-Slide Preparation of Caenorhabditis elegans toward Quantitative, High-Resolution LA-ICP-TOF Mass Spectrometry Imaging

Laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS) imaging is a powerful tool for spatially resolved elemental imaging in heterogeneous tissues. The nematode <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) is a well-established model organism for metal biology research.

However, there have been few reports on mass spectrometry-based metal imaging of <i>C. elegans</i> due to challenges in sample preparation for high-resolution and quantitative analysis. In this study, we established an integrated workflow consisting of sample preparation, imaging, and quantitative analysis for whole-animal elemental imaging of <i>C. elegans</i> by LA-ICP-TOF-MS. With the assistance of 3D-printed uniform layer media application tools (ULMATs), water-based and hydrocarbon-based embedding media were evaluated, and petrolatum, commercially known as Vaseline, stood out for its performance in preserving <i>C. elegans</i> over time for LA-ICP-TOF-MS imaging.