Fig. 1.

Physicochemical characterization of CCm₂₃₁-UCNPs. a Size intensity curves, b hydrodynamic size, and c zeta potential of UCNPs, CCm₂₃₁-UCNPs, and CCm₂₃₁ measured by dynamic light scattering (DLS). TEM images of d UCNPs, e CCm₂₃₁, and f, g CCm₂₃₁-UCNPs. The TEM samples were negatively stained with phosphotungstic acid. The scale bars = 20 nm. h SDS-PAGE protein analysis of MDA-MB-231 cancer cell lysate, cancer cell membrane vesicles, and CCm₂₃₁-UCNPs. Samples were run at equal protein concentration and stained with Coomassie Blue. i Western blotting analysis. Samples were run at equal protein concentration and immunostained against membrane markers including Na⁺/K⁺-ATPase, EGFR, histone H3 (a nuclear marker), and glyceraldehyde 3-phosphate dehydrogenase (a cytosolic marker). In vitro homologous-targeting ability and cytotoxicity of CCm₂₃₁-UCNPs. j Confocal laser scanning microscopy (CLSM) images of various cells after incubation with CCm₂₃₁-UCNPs. The scale bars = 100 μm. k Survival of MDA-MB-231 cells treated with different concentrations of CCm₂₃₁-UCNPs and UCNPs. The data points represent mean ± SD (n = 3)