A molecular paradigm: "Plug-and-play" chemical sensing and crypto-steganography based on molecular recognition and selective response.

Inspired by information processing and communication in nature based on molecular recognition and structural diversity, ongoing efforts aim to development of artificial molecular or nano-systems for sensing, logic computing, and even data storage and safety. However, due to their preparation/functionalization shortcomings (laborious and time-consuming), poor flexibility and compatibility, and limited paradigm, it is still a big challenge whether simple molecules can be used to achieve comprehensive and universal applications from sensing to information storage and protection. Herein, we for the first time demonstrated a molecular paradigm-computer-like "basic input output system (BIOS)" which can realize "plug-and-play" sensing, information encoding, molecular cryptography, and steganography based on a simple artificial molecule (p-nitrophenol, PNP). Based on its molecular recognition and inherent chemical identities, PNP was utilized for colorimetric detection of multiple metal ions (Hg ²⁺ , Fe ³⁺ , Al ³⁺ , Cr ³⁺ ) and distinguishing their valence (like Cr ³⁺ /Cr ⁶⁺ , Fe ³⁺ /Fe ²⁺ ). Interestingly, PNP can achieve the "plug-and-play" fluorescent expansion of detection channels by directly mixing with fluorescent molecules, indicating that PNP molecule can be served as a molecular BIOS with flexibility and compatibility. Impressively, the selectivity embedded in PNP-based BIOS sensing system can be developed as molecular-level double cryptographic steganography to encode, encrypt and hide specific information (like the content of classical literature). This research not only provides a basic idea for building a molecular paradigm with "plug-and-play" flexibility and compatibility, but also provides ideas for the use of molecular sensing and informatization to open up the digitalization of the molecular world.
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