Figure 5.

Cell enrichment analysis of MPI tracers using flow cytometry: Flow cytometry data represented as % enriched immune cell population (normalized to total cells counted) in the “Eluate” and “Column” content collected during and after magnetic separation of RBC lysed mouse blood using anti-Ly6G SPIOs, anti-F4/80 SPIOs and VivoTrax^TM. The control data represents the % of immune cells of interest (normalized to total cells counted) in unseparated RBC lysed blood samples. We were particularly interested in the granulocyte population (of which neutrophils are the largest subset) and the CD11b⁺ & Ly6G⁺ population. A significant enrichment of both granulocyte population and CD11b⁺ & Ly6G⁺ was observed in the “Column” using anti-Ly6G SPIOs. Anti-F4/80 SPIOs showed no enrichment of granulocytes or neutrophil population, which is expected due to lack of specificity to those populations. Finally, Vivotrax^TM showed significant enrichment of both granulocytes and neutrophil population (P<0.05 (**) and P<0.001 (***)) but the percentage relative enrichment in the “column” was not significant with respect to control (P> 0.05) (MPI: magnetic particle imaging; RBC: red blood cells; SPIO: superparamagnetic iron oxide).