ABSTRACT
We applied hybridization between hydrophobic peptide nucleic acids (PNAs) and oligodeoxynucleotides (ODNs) to achieve their cellular uptake without any need for transfection reagents. We employed a pyrenyl unit as a hydrophobic functional group and introduced it at the terminus of the PNA strand. The pyrene-tethered PNA (PyPNA) strongly bound with its complementary ODNs to generate amphiphiles; the resulting hybrids formed aggregates that showed efficient cellular uptake and high biological stability. Aggregates containing a functional DNA aptamer that bound to the PyPNA penetrated the cell membrane smoothly, with the aptamer exerting its original function in living cells. Thus, PyPNA efficiently assisted the additive-free cellular uptake of ODNs.
Subject(s)
Alveolar Epithelial Cells/metabolism , Lung/metabolism , Oligonucleotides/chemistry , Peptide Nucleic Acids/chemistry , Peptide Nucleic Acids/metabolism , A549 Cells , Alveolar Epithelial Cells/cytology , Biological Transport , Humans , Hydrophobic and Hydrophilic Interactions , Lung/cytology , TransfectionABSTRACT
Molecular oxygen in living cells is distributed and consumed inhomogeneously, depending on the activity of each organelle. Therefore, tractable methods that can be used to monitor the oxygen status in each organelle are needed to understand cellular function. Here we report the design of a new oxygen-sensing probe for use in the cell nucleus. We prepared "Ru-Hoechsts", each consisting of a phosphorescent ruthenium complex linked to a Hoechst 33258 moiety, and characterized their properties as oxygen sensors. The Hoechst unit shows strong DNA-binding properties in the nucleus, and the ruthenium complex shows oxygen-dependent phosphorescence. Thus, Ru-Hoechsts accumulated in the cell nucleus and showed oxygen-dependent signals that could be monitored. Of the Ru-Hoechsts prepared in this study, Ru-Hoechst b, in which the ruthenium complex and the Hoechst unit were linked through a hexyl chain, showed the most suitable properties for monitoring the oxygen status. Ru-Hoechsts are probes with high potential for visualizing oxygen fluctuations in the nucleus.
