New conjugated nucleic acid molecules and their uses

A conjugated nucleic acid molecule comprising a double-stranded nucleic acid moiety, the 5′ end of the first strand and the 3′ end of the complementary strand being linked together by a loop, and optionally a molecule facilitating the endocytosis which is linked to the loop,

• wherein
• the length of the double-stranded nucleic acid moiety is from 10 to 20 base pairs;
• the sequence of the double-stranded nucleic acid moiety has less than 80% sequence identity to any gene in a human genome;
• the double-stranded nucleic acid moiety comprises deoxyribonucleotides and up to 30% of ribonucleotides or modified deoxyribonucleotides with respect to the total number of nucleotides of the nucleic acid molecule;
• and
• the loop has a structure selected from one of the following formulae:
• —O—P(X)OH—O—{[(CH2)2—O]g—P(X)OH—O}r—K—O—P(X)OH—O—{[(CH2)2—O]h—P(X)OH—O—}s (I)
• with r and s being independently an integer 0 or 1;
• g and h being independently an integer from 1 to 7 and the sum g+h being from 4 to 7;
• with K being
• with i, j, k and 1 being independently an integer from 0 to 6;
• or
• —O—P(X)OH—O—[(CH2)d—C(O)—NH]b—CHR—[C(O)—NH—(CH2)e]c—O—P(X)OH—O— (II)
• with b and c being independently an integer from 0 to 4, and the sum b+c is from 3 to 7;
• d and e being independently an integer from 1 to 3;
• and
• with R being -Lf-J,
• X being O or S, L being a linker and f being an integer being 0 or 1, and J being a molecule facilitating the endocytosis or being H.