Fig. 2

Characterization of rmDPPs. (a) Schematic illustration of rmDPPs. (b) Detected Fe and S in rmDPPs using energy-dispersive X-ray spectroscopy (EDS) analysis, indicating that SPIONs and rtPA were successfully localized within the PLGA matrix (0.84 wt % for Fe; 1.70 wt % for S, \(n=3\)). (c) Geometric features observed in the scanning electron microscope (SEM) and microscopic images, showing rmDPPs were disc-shaped and uniformly synthesized. (d) No dramatic changes in initial size in rmDPPs, indicating loading SPIONs and rtPA into PLGA did not affect the inherent size of DPPs (\(n=3\)). (e) Increased drug loading with the rtPA input (\(n=3\)). (f-g) Schematic illustration and images of recruited rmDPPs depending on reaction time with 30 min intervals, showing that rmDPPs could be localized into the external magnetic field (vertical magnetic field: 0.42 T, \(n=3\)). (h-i) Quantification of recruitment efficacy and presentation of magnetization, indicating that rmDPPs demonstrated superparamagnetic properties (\(n=3\))