Fig. 1

In vitro characterization of hybrid membrane RAW-4T1 and DPLGA@[RAW-4T1] NPs. a 4T1 membrane doped with DOPE-RhB and C6-NBD and mixed with an increasing ratio of RAW. The fusion process was monitored as the florescence recovery of the donor (C6-NBD, excitation/emission = 460/534 nm) (4T1: RAW = 4T1 membrane to RAW264.7 membrane protein ratio). b Western blot analysis of 4T1, RAW, RAW-4T1 membrane, and DPLGA@[RAW-4T1] NPs for characteristic 4T1 membrane markers VCAM-1, and characteristic RAW264.7 membrane markers α4 (Na⁺-K⁺-ATPase was used as a reference protein). c SDS-PAGE analysis of protein retention (1: 4T1, 2: RAW, 3: RAW-4T1 membrane, and 5: DPLGA@[RAW-4T1] NPs). d Immunogold TEM images of RAW, 4T1, RAW-4T1, and DPLGA@[RAW-4T1] NPs samples probed for α4 (red arrows, large gold) and VCAM-1 (yellow arrows, small gold), after negative staining with 2% sodium phosphotungstate (scale bar = 50 nm). e Images captured by confocal florescent microscopy for the mixture of PLGA@RAW NPs, PLGA@4T1 NPs, and PLGA@[RAW-4T1] NPs (red = 4T1 membrane, green = RAW membrane; scale bar = 5 µm). f Representative TEM images of DPLGA NPs, DPLGA@RAW NPs, and DPLGA@4T1 NPs, and DPLGA@[RAW-4T1] NPs negatively stained with vanadium (scale bar = 50 nm). g Z-average size of bare DPLGA NPs, DPLGA@4T1 NPs, DPLGA@RAW NPs and DPLGA@[RAW-4T1] NPs were determined by DLS. Data are presented as the mean ± SD (n = 3). h Zeta potential of DPLGA NPs, RAW, 4T1, RAW-4T1, DPLGA@RAW NPs, DPLGA@4T1 NPs, and DPLGA@[RAW-4T1] NPs, (n = 3; mean ± SD). i Quantification of total proteins on DPLGA@[RAW-4T1] NPs by BCA assay after incubating different amount of RAW-4T1 to the bare PLGA NPs at different membrane-to-polymer weight ratios (w/w). j Z-average size of bare DPLGA NPs, DPLGA@4T1 NPs, DPLGA@RAW NPs, and DPLGA@[RAW-4T1] NPs, over 2 weeks in PBS (pH 7.4) (n = 3; mean ± SD)