Nanospray desorption electrospray ionization (nano-DESI) is an ambient ionization technique that enables molecular imaging of biological samples with high spatial resolution. We have recently developed an integrated microfluidic probe (iMFP) for nano-DESI mass spectrometry imaging (MSI) that significantly enhances the robustness of the technique. Herein, we report the design and performance of a second-generation iMFP for imaging with high spatial resolution. The new iMFP features smaller primary and spray channels and a new configuration of the sampling port that enables robust imaging of tissues with a spatial resolution of 8-10 µm. We demonstrate the spatial resolution, sensitivity, durability, and throughput of the iMFP by imaging mouse uterine and brain tissue sections. With a scan rate of 0.2 mm/s, we obtained high-resolution images of a mouse uterine tissue section (scanned area: 2.9 mm × 3.2 mm) in less than 29 minutes without sacrificing sensitivity. This corresponds to a 10-fold improvement in the experimental throughput in comparison with previously reported high-resolution nano-DESI MSI experiments. Overall, the new probe design opens opportunities for mapping biomolecules in biological samples with high throughput and cellular resolution, which is important for understanding biological systems.
additional experimental details and data