Porous graphene films-enabled mass spectrometry imaging reveals metabolic asymmetry in mice after single-dose ethanol intoxication

We introduce laser-induced graphene (LIG) as an innovative substrate for laser desorption/ionization mass spectrometry imaging (LDI-MSI). The three-dimensional porous structure of LIG facilitates efficient ultraviolet laser energy absorption, thereby improving desorption/ionization efficiency while conserving laser energy and enables the trapping of analytes, thereby enhancing sensitivity. The LIG substrate exhibits little background interference and favorable signal homogeneityand achieves 3-μm spatial resolution in MSI without requiring matrix spraying, realizing a significantly simplified MSI procedure. Using LDI-MSI with a LIG substrate, we revealed spatial metabolic asymmetry in nine lipid species in the brains of mice after single-dose ethanol intoxication, accompanied by pronounced temporal dynamics. The brain lipid distribution displayed dynamic laterality shifts, with the left side showing significantly lower levels of nine lipid species compared to the right at 30 min, near-bilateral equilibration by 4 h, andthe left side showing higher levels than the right side at 24 h.