ABSTRACT Stable polymersomes with semipermeable membranes were prepared by simple mixing two oppo... more ABSTRACT Stable polymersomes with semipermeable membranes were prepared by simple mixing two oppositely charged diblock copolymers containing zwitterionic and cationic (PMPC20-b-PMAPTAC190) or anionic (PMPC20-b-PAMPS196) blocks. The formation of vesicular structures in the mixed solution of the block copolymers was confirmed by direct observation with cryo-TEM technique. Superparamagnetic iron oxide nanoparticles coated with cationic chitosan derivative (SPION/CCh) and these decorated with a fluorescent probe molecule were next incorporated into the polymersome structure. The average diameter of SPION/CCh-polymersomes estimated with cryo-TEM was about 250 nm. Surface topography of the SPION/CCh-loaded vesicles was imaged using AFM and magnetic properties of these objects were confirmed by MFM and MRI measurements. The ability of the SPION/CCh-polymersomes to affect T2 relaxation time in MRI was evaluated based on the measurements of r2 relaxivity. The obtained value of r2 (573 ± 10 mM-1s-1) was quite high. The cytotoxicity and intracellular uptake of the SPION/CCh-loaded vesicles into EA.hy926 cells were studied. The results indicate that the SPION/CCh-polymersomes seem to be internalized by vascular endothelium and are not cytotoxic to endothelial cells up to 1 μg Fe/ml. Therefore, it can be suggested that the SPION/CCh-polymersomes could prove useful as T2 contrast agents in MRI of endothelium.
ABSTRACT Stable polymersomes with semipermeable membranes were prepared by simple mixing two oppo... more ABSTRACT Stable polymersomes with semipermeable membranes were prepared by simple mixing two oppositely charged diblock copolymers containing zwitterionic and cationic (PMPC20-b-PMAPTAC190) or anionic (PMPC20-b-PAMPS196) blocks. The formation of vesicular structures in the mixed solution of the block copolymers was confirmed by direct observation with cryo-TEM technique. Superparamagnetic iron oxide nanoparticles coated with cationic chitosan derivative (SPION/CCh) and these decorated with a fluorescent probe molecule were next incorporated into the polymersome structure. The average diameter of SPION/CCh-polymersomes estimated with cryo-TEM was about 250 nm. Surface topography of the SPION/CCh-loaded vesicles was imaged using AFM and magnetic properties of these objects were confirmed by MFM and MRI measurements. The ability of the SPION/CCh-polymersomes to affect T2 relaxation time in MRI was evaluated based on the measurements of r2 relaxivity. The obtained value of r2 (573 ± 10 mM-1s-1) was quite high. The cytotoxicity and intracellular uptake of the SPION/CCh-loaded vesicles into EA.hy926 cells were studied. The results indicate that the SPION/CCh-polymersomes seem to be internalized by vascular endothelium and are not cytotoxic to endothelial cells up to 1 μg Fe/ml. Therefore, it can be suggested that the SPION/CCh-polymersomes could prove useful as T2 contrast agents in MRI of endothelium.
Uploads
Papers by Gabriela Kania