Despite these advantages, DESI-MSI also faces several limitations when applied to single-cell analysis. One of the primary challenges is achieving sufficient spatial resolution to differentiate individual cells accurately. The typical spatial resolution of DESI-MSI is limited to around 35 µm, which can be insufficient for single-cell imaging, where cells may be as small as 10-20 µm. For a given analytical technique, sensitivity and resolution (including the spatial resolution) are inversely proportional to each other, i.e., increasing the MSI spatial resolution reduces its sensitivity due to reduced amounts of analytes. An effective approach to increasing the sensitivity of high spatial resolution MSI technique is to increase its efficiencies of molecular ionization and ion transfer. The efficiencies of molecular ionization and ion transfer in DESI-MSI can be affected by multiple factors (e.g., the sample's surface properties, the spray angle and distance, the voltage applied to the spray, the solvent composition, and the flowrate of the solvent) that can lead to variability in signal intensity and complicate quantitative analyses. Because analyte ions need to be transferred from the surface into the mass spectrometer through an ion transfer capillary, ion signal loss can occur due to several factors (e.g., ion neutralization, ion attachment to surfaces within the capillary, and incomplete transfer of ions ) that can reduce the overall ions' intensities. Reducing ion loss during transfer is regarded as an effective strategy. A previous study by Zickuhr et al. (2024) showed that heating the ion transfer capillary from 150°C to 450°C resulted in up to a 1.8-fold increase in overall signal intensity. We aimed to improve the detection sensitivity of the DESI experiments by optimizing the experimental conditions, including heating the ion transfer capillary, to acquire MS images of single cells.