An Oligonucleotide Delivery Platform to Enable Assessment of Intracellular Transcripts in Live Cells by Flow Cytometry.

The measurement of mRNA transcripts in live cells has been limited by inefficient delivery vehicles for oligonucleotides. Using a delivery platform which utilizes fluorophores capable of forming intramolecular H-type excitonic dimers, we show that antisense oligonucleotides (ASOs) can be delivered across the plasma membrane directly into the cytosol without receptor mediation. With HIV infection of CD4 lymphocytes as a model system, we quantitate the level of viral infection present in live single cells with flow cytometry by measuring the hybridization of ASOs to viral sequences; we then compare this measurement with a standard HIV analysis, that is, binding of an antibody against the HIV cell surface protein gp120.