*2.11. Cells Transfection*

One day before the carrier-free transfection procedure, cells were seeded in 24-well plates at a density of 1.2 <sup>×</sup> 105 cells/well. Then cells were washed with PBS and treated for 4 h with a medium containing fluorescently labeled dodecyl oligonucleotide conjugate FAM-D-17PG or duplex D-17PG/FAM-17- (250 μL/well). We used six versions of the medium composition for cell transfection procedure: (a,d) fresh DMEM (245 μL) and FAM-D-17PG or D-17PG/FAM-17- (5 μL, 250 μM); (b,e) fresh DMEM with 10% FBS (245 μL) and FAM-D-17PG or D-17PG/FAM-17- (5 μL, 250 μM); (c,f) fresh DMEM (240 μL), filtered through 0.45 μm bovine serum albumin (5 μL, 1.5 mM) and FAM-D-17PG or D-17PG/FAM-17-(5 μL, 250 μM). For each condition, three independent transfections were prepared.
