(16e) Membrane Outer Leaflet Is the Primary Regulator of Membrane Damage Induced By Silica Nanoparticles in Vesicles and Red Blood Cells
AIChE Annual Meeting
2019 AIChE Annual Meeting
Engineering Sciences and Fundamentals
Biomolecules at Interfaces I
Sunday, November 10, 2019 - 4:30pm to 4:45pm
Vesicle integrity was studied by encapsulating the self-quenching fluorescent probe, carboxyfluorescein, in vesicles and studying its leakage after exposure to 0.0001-0.01 g/L of nanoparticles at 37 °C. Confocal fluorescence microscopy performed on giant unilamellar vesicles (GUVs) was used to monitor nanoparticle effects on vesicle morphology. Förster Resonance Energy Transfer (FRET) experiments were employed to examine particle localization at the membrane. Finally, nanoparticle-induced hemolysis was evaluated by measuring the absorbance of hemoglobin released from red blood cells after incubation with 0.01 g/L of nanoparticles at 37 °C.
Vexo and Vcyto vesicles showed significant difference in their interactions with nanoparticles. Vexo vesicles showed drastic leakage of intravesicular content after exposure to plain and amine-modified particles while none of the particles caused significant leakage in Vcyto vesicles. FRET experiments revealed that nanoparticle-induced disruption by plain and amine-modified particles occurs via pore formation. In agreement, FRET assay and GUV images revealed significant localization of plain and amine-modified particles at the surface of the Vexo vesicles. However, no localization was observed with the Vcyto vesicles. Interestingly, symmetric and asymmetric vesicles were disrupted similarly by plain and amine-modified particles. Importantly, hemolysis was observed after the incubation of RBCs with plain and amine-modified particles, consistent with leakage assays using Vexo vesicles. In conclusion, these results suggest that the outer leaflet of the plasma membrane is the primary regulator of nanoparticle-induced membrane damage in RBCs. Future studies focused on the understanding the role of outer leaflet lipids in regulating ENM-membrane interactions in live cells.