A Robotic Sample Handling Platform for Fully Automated Nanospray Desorption Electrospray Ionization Mass Spectrometry Imaging

Recent advances in mass spectrometry imaging (MSI) have enabled high-throughput experiments, making it possible to image multiple samples and perform three-dimensional molecular mapping. For these applications, automated sample handling is critical. Here, we present the first fully automated nanospray desorption electrospray ionization (nano-DESI) MSI platform that integrates robotic sample handling with automated sample recognition system. A robotic arm, controlled by our custom LabVIEW program, automatically places samples onto a sample holder and removes them after the analysis. The sample holder, mounted on a motorized XYZ stage, is automatically transferred to a mass spectrometer for imaging. A newly developed on-site sample region recognition system enables on-the-fly identification of sample coordinates and transfers them to LabVIEW, which plans and executes the imaging experiment. A microfluidic nano-DESI probe (MFP) was used due to its robustness and high-throughput capability. Shear force feedback distance control was incorporated into the MFP to address height variations across multiple glass slides. Using this system, five mouse brain tissue sections on two glass slides were imaged sequentially with high reproducibility and consistency, without human intervention. These results demonstrate the feasibility and performance of a fully automated nano-DESI MSI workflow, paving the way for multisample and three-dimensional MSI experiments.