Photoresponsive DNA steganography for secure information transmission by nanopore

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 <10 minutes. Collectively, this work provides fresh insights into balancing density, security and efficiency, advancing DNA steganography toward secure and instantaneous messaging applications.