Plasmonic Gold Templates Enhancing Single Cell Lipidomic Analysis of Microorganisms

Single cell lipid profiling is a powerful tool to connect membrane composition and its changes within individual cells to specific biochemical functions or stimuli, but current approaches are inadequate due to the complex nature of the cells and technical limitation in analysis. Herein we report a new method with plasmonic substrates capable of cell localization and enhanced lipid ionization through thin-gold-film MALDI-MS. We performed lipidomic profiling of algae single cells with a 120-well microarray and identified more than 50 lipids in C. reinhardtii without an extraction process. The substrate was used for probing toxicological effect of herbicide atrazine on the algae's lipidome, demonstrating molecular changes in glycerol lipid profiles. Fast location of cells with metal-enhanced fluorescence (MEF) and subsequent precise and direct ionization of the LDI process contribute to the enhanced performance, allowing for assessment of lipid changes concurrent with atrazine affected populations. This method that combines microarrays, MEF, and MALDI-MS presents an effective platform for lipidomic study of single cells and for environmental toxicity study with microorganisms.