We're trying to make fluorescent-labelled liposomes for ex vivo drug delivery studies, and are considering using either :

Lissamine™ Rhodamine B 1,2-Dihexadecanoyl-sn-Glycero-3-Phosphoethanolamine, Triethylammonium Salt (rhodamine DHPE)

or

1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (ammonium salt)

Which one of these would be better for this purpose, and what difference does it make if I choose Rhodamine PE over Rhodamine DHPE or vice versa?