DNA Cage Delivery to Mammalian Cells

TLDR

DNA cages are nanometer‑scale polyhedral structures self‑assembled from synthetic DNA oligonucleotides, with potential applications in in‑vivo imaging and targeted delivery of macromolecules into living cells, representing a first step toward using engineered DNA nanostructures to deliver and control cargo activity within cells. We investigate whether a DNA tetrahedron can enter live cultured mammalian cells. Human embryonic kidney cells were treated with fluorescently labeled DNA tetrahedra across a range of concentrations and examined by confocal microscopy and flow cytometry. Tetrahedra were substantially taken up by the cells, localizing to the cytoplasm, and remained largely intact for at least 48 h, whether delivered alone or with a transfection reagent.

Abstract

DNA cages are nanometer-scale polyhedral structures formed by self-assembly from synthetic DNA oligonucleotides. Potential applications include in vivo imaging and the targeted delivery of macromolecules into living cells. We report an investigation of the ability of a model cage, a DNA tetrahedron, to enter live cultured mammalian cells. Cultured human embryonic kidney cells were treated with a range of fluorescently labeled DNA tetrahedra and subsequently examined using confocal microscopy and flow cytometry. Substantial uptake of tetrahedra into cells was observed both when the cells were treated with tetrahedra alone and when the cells were treated with a mixture of tetrahedra and a transfection reagent. Analysis of the subcellular localization of transfected tetrahedra using confocal microscopy and organelle staining indicates that the cages are located in the cytoplasm. FRET experiments indicate that the DNA cages remain substantially intact within the cells for at least 48 h after transfection. This is a first step toward the use of engineered DNA nanostructures to deliver and control the activity of cargoes within cells.