A journey from the endothelium to the tumor tissue: distinct behavior between PEO-PCL micelles and polymersomes nanocarriers

Figures & data

Figure 1. Micelles (PEO-PCL 5-4) and polymersomes (PEO-PCL 5-11) size and charge characterizations: Transmission electron microscopy (A,B); DLS analyses (C); nanoparticle tracking analyses (D); and UV-vis analyses (E).

Table 1. Micelles and polymersomes physicochemical analysis: DLS hydrodynamic diameter (D_H) in number and intensity average, NTA hydrodynamic diameter, and Zeta potential measurements.

	Empty	Charged with 2% mol DiO
Micelles PEO-PCL 5-4 DH in number average (nm) DH in intensity average (nm) Zeta potential (mV)	14 ± 1 24 ± 0 −13 ± 3	14 ± 2 25 ± 4 −11 ± 4
Polymersomes PEO-PCL 5-11 DH in number average (nm) DH in intensity average (nm) NTA diameter (nm) Zeta potential (mV)	72 ± 6 135 ± 11 111 ± 9 −4 ± 1	65 ± 5 117 ± 10 93 ± 10 −3 ± 1

Figure 2. Quantification by flow cytometry of internalization of micelles and polymersomes charged with DiO in HUVEC and HCT-116: kinetics in monoculture (A,B) and 24 h internalization in co-culture (C,D).

Figure 3. DiO penetration in 3D tumor spheroid depending on the nanocarriers: two-photon microscopy images of the mean intensity projection of DiO fluorescence from HCT-116 spheroids exposed for 24 h to micelles (A) and polymersomes (B). C and D are optical sections at z = 50 µm depth of the spheroid A and B, respectively.

Figure 4. Quantification of nanocarriers’ passage across the endothelium barrier after 24 h of incubation: DiO fluorescence in the receptor chamber (A), Anthracene fluorescence in the receptor chamber (B), DiO fluorescence in the receptor chamber in pro-inflammatory condition (C), DiO fluorescence in the receptor chamber in presence of tumor HCT-116 (D). Intracellular quantification of nanocarriers by flow cytometry: proportion of labeled cells (E), intensity of DiO fluorescence in labeled cells (F). *p < .05. NS: non-significant difference. For each nanocarrier, the DiO fluorescence was significantly lower in the healthy condition compared to the disturb conditions (with TNF-α or in coculture).

Figure 5. Macroscopic and microscopic (cryosection) fluorescent pictures of explanted HCT-116 tumors 24 h after retro-orbital injection in mice of 100 µL of PBS (A,E), DiO alone (B,F), micelles charged with 20% mol DiO (C,G), or polymersomes charged with 20% mol DiO (D,H). DiO fluorescence (green), and in cryosection nuclei stained with Hoechst (blue), and CD-31+ murine endothelial cells detected by immunofluorescence (red).