Synthesis of novel cationic spermine-conjugated phosphotriester oligonucleotide for improvement of cell membrane permeability

Abstract

A spermine-conjugated ethyl phosphotriester oligonucleotide was obtained by solid-phase synthesis based on phosphoramidite chemistry. The ethyl phosphotriester linkage was robust to exonuclease digestion and stable in fetal bovine serum. Cell membrane permeability of the spermine-conjugated ethyl phosphotriester oligonucleotide was studied by fluorescence experiments. The effective cell penetrating potency of the spermine-conjugated ethyl phosphotriester oligonucleotide was determined by confocal laser scanning microscopy and measurement of intracellular fluorescence intensity.

Keywords: Cationic oligonucleotide; Cellular uptake; Phosphotriester; Spermine.