Graphene-Coated Glass Substrate for Continuous Wave Laser Desorption and Atmospheric Pressure Mass Spectrometric Imaging of a Live Hippocampal Tissue

The atmospheric pressure mass spectrometric (AP-MS) imaging technology combined with an inverted optical microscopic system is a powerful tool for determining the presence and spatial distributions of specific biomolecules of interest in live tissues. Efficient desorption and ionization are essential to acquire mass spectrometric (MS) information in an ambient environment. In this study, we demonstrate a new and efficient desorption process using a graphene-coated glass substrate and a continuous wave (CW) laser for high-resolution AP-MS imaging of a live hippocampal tissue. We found that desorption of biomolecules in a live tissue slice was possible with the aid of a graphene-coated glass substrate and indirect application of a 532 nm CW laser on the graphene substrate. Interestingly, the desorption efficiency of a live tissue on the graphene-coated substrate was strongly dependent on the number of graphene layers. Single-layer graphene was found to be the most sensitive substrate for efficient desorptio...