Photoresponsive DNA steganography for secure information transmission by nanopore

ABSTRACT Conventional DNA encryption methods often require additional noncoding strands as physical keys or covering media, leading to a density decrease from redundancy. Here, we present a nanopore-based photoresponsive DNA information steganography system (NAPDISS) that encodes 26 encrypted English letters by using only five isomerizable azobenzene-modified coding DNAs, thereby eliminating the need for extra synthesis. Encoding was implemented through two complementary schemes comprising a letter code with sequence-defined photoresponsive DNAs representing letters and an address code with poly(dA)3 (A3) concentrations defining the letters’ positions. Utilizing light as secret keys, NAPDISS conceals messages by obscuring the nanopore readouts, allowing recovery only through combined pre- and post-irradiation analyses. This approach achieves a logical storage density of 0.2–1.0 bits per nucleotide—about one order of magnitude higher than those of existing DNA-structure-based methods. Moreover, simplified sample processing reduces the readout time from hours to