Cellular endocytosis and trafficking of cholera toxin B-modified mesoporous silica nanoparticles

Abstract

In this study, mesoporous silica nanoparticles (MSNs) were functionalized with cholera toxin subunit B (CTxB) protein to influence their intracellular trafficking pathways. The CTxB–MSN carrier was synthesized, and its chemical and structural properties were characterized. Endocytic pathway inhibition assays showed that the uptake of CTxB–MSNs in human cervical cancer (HeLa) cells was partially facilitated by both clathrin- and caveolae-mediated endocytic mechanisms. Laser scanning confocal microscopy (LSCM) experiments demonstrated that CTxB–MSNs were taken up by the cells and partially trafficked through the trans-Golgi network into the endoplasmic reticulum in a retrograde fashion. The delivery abilities of CTxB–MSNs were evaluated using propidium iodide, an impermeable cell membrane dye. LSCM images depicted the release of propidium iodide into the endoplasmic reticulum and the cell nucleus of HeLa cells.