Bacteriomimetic invasin-functionalized nanocarriers for intracellular delivery

Intracellular bacteria invade mammalian cells to establish an infectious niche. The current work models adhesion and subsequent internalization strategy of pathogenic bacteria into mammalian cells to design a bacteriomimetic bioinvasive delivery system. We report on the surface functionalization of liposomes with a C-terminal fragment of invasin (InvA497), an invasion factor in the outer membrane of Yersinia pseudotuberculosis. InvA497-functionalized liposomes adhere to mammalian epithelial HEp-2 cell line at different infection stages with a significantly higher efficiency than liposomes functionalized with bovine serum albumin. Covalent attachment of InvA497 results in higher cellular adhesion than liposomes with physically adsorbed InvA497 with non-specific surface protein alignment. Uptake studies in HEp-2 cells indicate active internalization of InvA497-functionalized liposomes via β1-integrin receptor-mediated uptake mechanism mimicking the natural invasion strategy of Y. pseudotuberculosis. Uptake studies in Caco-2 cells at different polarization states demonstrate specific targeting of the InvA497-functionalized liposomes to less polarized cells reflecting the status of inflamed cells. Moreover, when loaded with the anti-infective agent gentamicin and applied to HEp-2 cells infected with Y. pseudotuberculosis, InvA497-functionalized liposomes are able to significantly reduce the infection load relative to non-functionalized drug-loaded liposomes. This indicates a promising application of such a bacteriomimetic system for drug delivery to intracellular compartments.