Fig. 2.

Characterization of Eu-FBCP and Eu-s in the absence and presence of PTX. a, b High- and low-magnification SEM images of Eu-s/Cy5.5 and Eu-FBCP/Cy5.5 from electrosprays of Cy5.5 containing Eu liquid. Similarly sized Eu-s/Cy5.5 was prepared by controlling the concentration of Eu dissolved in ethanol in the absence of air injection into the inner nozzle. c–f FACS results (n = 3; fluorescence profile and mean fluorescence intensity [MFI]) for comparing cellular uptake in MC-38 (c, d) or B16 (e, f) cells between Eu-FBCP and Eu-s after adding Cy5.5 to the electrosprays to examine the greater uptake of Eu-FBCP because of the concave shape. This assay included Eu RL to confirm the differences in uptake between the Eu RS and Eu RL for justification of the selection of Eu RS. g DLS size distribution of Eu-FBCP/PTX dispersed in PBS (inset digital image) exhibiting mean size and PDI. h, i High- and low-magnification SEM (h) and TEM (i) images of Eu-FBCP/PTX. j Representative TEM images of Eu-FBCP/PTX after 8 h dispersion in DW, PBS, or RPMI + 10% FBS to examine the hydrodynamic stabilities for different media. k In vitro release profiles of PTX from Eu-FBCP/PTX for 48 h dispersion at pH 6.5 or pH 7.4 (n = 3). l XRD spectra of Eu-FBCP/PTX and Eu-s/PTX, as well as free PTX and Eu (RS; before the electrosprays), to examine and compare incorporation between Eu and PTX. m Hemolysis results from 8 h incubation of red blood cells with Eu-FBCP/PTX or Eu-s/PTX at different concentrations (50–400 µg mL⁻¹) (n = 3; **p < 0.01 and **p < 0.001). Insets show representative digital images of the incubated dispersions