Self-assembled monolayers of chiral periodic mesoporous organosilica as a stimuli responsive local drug delivery system

We present the preparation of self-assembled monolayers (SAMs) of pH responsive chiral periodic mesoporous organosilicas (PMOs) as model implants with drug delivery ability. SAMs of pH responsive PMOs were prepared by layer-by-layer coating of PMOs with polyelectrolytes ( e.g. the enantiomers of a polycation biopolymer), for delivering organic molecules and anticancer drug molecules locally in a controlled manner to the adhered cells. We demonstrate that the amount of primary fibroblast, immortal NIH 3T3, and malignant Colo 818 cells adhered to the SAM of the d -enantiomer of polycation-functionalized PMOs was higher in comparison to that of the l -enantiomer of the polycation-functionalized PMO monolayer. In addition, we observe that the 3T3 and Colo cells internalized more of the organic and anticancer drug molecules (released from pH responsive PMOs) than the primary cells did due to the local acidic environment of them. Therefore, as the chirality of the PMOs influenced the amount of cells that adhered, the released molecules interacted with different amounts of cells which allowed us to tune the extent of local drug delivery. pH responsive PMOs deliver higher dosages of drugs to malignant cells while delivering less of the drugs to healthy cells.