*2.3. Oligonucleotides and Conjugates Synthesis*

Standard phosphoramidite solid-phase synthesis of all modified/unmodified and conjugated/ unconjugated oligonucleotides was carried out on the ASM-800 DNA/RNA synthesizer (Biosset, Novosibirsk, Russia). Oligonucleotides were synthesized at 0.2 μmol scale, using standard commercial 2-cyanoethyl deoxynucleoside phosphoramidites and CPG solid supports (Glen Research, Sterling, VA, USA). The phosphoramidite for introducing non-nucleosidic dodecyl-containing units was obtained as described [36] and used as a 0.1 M solution in anhydrous acetonitrile with the extension of the coupling time from 1 to 10 min. Oligonucleotides with internucleoside uncharged phosphoryl 1,3-dimethylimidazolidine-2-imino groups (phosphoryl guanidines, PG) were synthetized by NooGen LLC as described earlier [37–39]. 6-carboxyfluorescein (FAM) labeling of the oligonucleotides was performed using commercially available 5- - and 3- -modifiers (2-Dimethoxytrityloxymethyl-6-(3- ,6- -dipivaloylfluorescein-6-yl-carboxamido)-hexyl-1-*O*-[(2-cyanoethyl)- (*N*,*N*-diisopropyl)]-phosphoramidite from Glen Research, Sterling, VA, USA and 3- -FAM-CPG (Figure S1) from Primetech ALC, Minsk, Belarus) according to the manufacturer's protocols. All oligomers after cleavage and deblocking from CPG were purified by RP-HPLC and their structures (for examples see Figures S3–S5) were confirmed by MALDI TOF or ESI mass spectrometry (for additional information see Supp. Inf., Section S1, Table S1, Figure S6).
