Using a FRET-capable oligonucleotide molecular beacon (OMB), we monitored the transport of intact DNA to cell organelles. 
FRET
Using a FRET-capable oligonucleotide molecular beacon (OMB), we monitored the transport of intact DNA to cell organelles.  We observed that for effective (jetPEI) and ineffective (G5 PAMAM) vectors, the fraction of cells displaying intact OMB in the cytosol (jetPEI ≫ G5 PAMAM) quantitatively predicted the fraction expressing transgene (jetPEI ≫ G5 PAMAM).  Intact OMB delivered with PAMAM and confined to endosomes could be released to the cytosol by the subsequent addition of L-PEI, with a corresponding 10-fold increase in transgene expression. 
OMB