Mass-tag barcoding for multiplexed analysis of human synaptosomes and other anuclear events

Mass-tag cell barcoding has increased the throughput, multiplexing, and robustness of multiple cytometry approaches. Previously, we adapted mass cytometry for cells to analyze synaptosome preparations (mass synaptometry or SynTOF), extending mass cytometry to these smaller, anuclear particles. To improve throughput and individual event resolution, we report here the application of palladium-based barcoding in human synaptosomes. Up to 20 individual samples, each with a unique combinatorial barcode, were pooled for labeling with an antibody cocktail. Our synaptosome protocol used six palladium-based barcoding reagents, and in combination with sequential gating increased the identification of presynaptic events approximately fourfold. These same parameters also efficiently resolved two other anuclear particles: human red blood cells and platelets. The addition of palladium-based mass-tag barcoding to our approach improves mass cytometry of synaptic particles.