leukocytes (5 × 105, 100 μL) were plated per
well of a sterile 96-well round-bottom plate (Falcon, Corning) and
mixed with 5 μL of BODIPY-labeled polymersomes in a cell:particle
ratio of 1:5 or 1:50. A polymer amount of 0.385 mg was estimated to
correspond to 5 × 109 polymersomes. To block particle
uptake, leukocytes were incubated with Cytochalasin D (Sigma) at a
final concentration of 10 mM for 15 min at 37 °C, prior to adding
polymersomes. The cells were incubated with polymersomes for 30 or
60 min at 37 °C, 250 rpm. Subsequently, the cells were stained
with LIVE/DEAD Fixable Dead Cell Stain Kit-Far Red (Invitrogen) according
to manufacturer’s recommendations and followed by fluorescent
labeling of cell markers: CD45-BV510 (clone HI30, BD Biosciences),
CD14-PE-Cy7 (clone HCD14, Biolegend), CD66b-BV421 (clone G10F5, BD
Biosciences), CD56-PE (clone C5.9, Cytognos, Spain), and CD3-APC-Cy7
(clone SK7, BD Biosciences). Flow cytometry data were collected on
a BD LSR II (BD Biosciences) and analyzed using FlowJo 10.2 Software
(
events were excluded from the data analysis.