*2.7. Particle-Cell Association Studies*

BMMΦs and RAW 264.7 cells were seeded in sterile 24-well plates at a concentration of 0.2 <sup>×</sup> <sup>10</sup><sup>6</sup> cells/well and then treated with 30 µg/mL of Cy5.5-labeled iNPs (PLA-PEMA and PLA-PVA) for 1 hr. All treated wells were washed twice with PBS to remove excess iNPs and replenished with 500 µL of fresh sterile PBS. For fluorescence microscopy, cells were either visualized immediately or fixed with 4% paraformaldehyde prior to visualization with either an ECHO (San Diego, CA, USA) Revolve benchtop fluorescence microscope or Nikon (Tokyo, Japan) Eclipse Ti-E confocal microscope. For flow cytometry, cells were scraped using a blunt 1000 µL pipette tip followed by collection by centrifugation and stained for viability using DAPI dye. Flow cytometry was used to measure Cy5.5 signal on viable (DAPI−) cells.
