Cholesterol Anchors Enable Efficient Binding and Intracellular Uptake of DNA Nanostructures.

DNA nanostructures constitute a rapidly advancing tool-set for exploring cell-membrane functions and intracellular sensing or advancing delivery of biomolecular cargo  into cells. Chemical conjugation with lipid anchors can mediate binding of DNA nanostructures to synthetic lipid bilayers, yet how such structures interact with biological membranes and internalize cells has not been shown. Here, an archetypal 6-duplex nanobundle is used to investigate how lipid conjugation influences DNA cell binding and internalization kinetics. Cellular interactions of DNA nanobundles modified with one and three cholesterol anchors were assessed using flow cytometry and confocal microscopy. Nuclease digestion was used to distinguish surface-bound DNA, which is nuclease accessible, from internalized DNA. Three cholesterol anchors were found to enhance cellular association by up to 10-fold when compared with unmodified DNA. The bundles were endocytosed efficiently within 24 h. The results can help design controlled DNA binding and trafficking into cells.