Modified polynucleotide

A method comprising introducing a composition comprising a modified polynucleotide into a cell in vitro or in vivo,

• wherein the modified polynucleotide is modified by a molecule that contains a structure represented by general formula (1):
• wherein, R1 and R2 are identical or different and represent a single bond or a divalent group optionally containing at least one group selected from the group consisting of —S—S— and —SH;
• R3 represents —O— or —O—R31, wherein R31 represents a monovalent group optionally containing at least one group selected from the group consisting of —S—S— and —SH;
• Z1 is —O— or —NH—;
• provided that at least one of R1, R2, and R3 contains at least one group selected from the group consisting of —S—S— and —SH;
• and n is an integer from 3 to 30, wherein
• the structure represented by general formula (1) is linked to a terminal of the polynucleotide.