Iron‐Doped Cobalt Molybdate Enhanced Electrochemiluminescence Imaging for Dynamic Multilevel Information Encryption System Construction and Biomarker Sensing Analysis

Abstract Integrating electrochemiluminescence (ECL) imaging with a multilevel information encryption strategy overcomes the limitations of conventional encryption methods, which rely solely on abstract electrical signals, by providing intuitive visual outputs. Herein, a dynamic multilevel information encryption system based on ECL imaging was successfully constructed, which realizes robust protection and precisely controlled decryption of information through the multidimensional security mechanism of “biometrics (biospecific recognition of the primary key) – electrochemical activation (precise voltage‐triggered activation of the secondary key) – operational sequence dependence (strict matching of the operational timing)–signal gradient (decryptor judgment)”. Specifically, we develop a functional chemical ink comprised of iron‐doped cobalt molybdate and biomolecules, which is applied onto nitrocellulose membranes via micro‐patterned printing to construct biocompatible, environmentally responsive encryption interfaces. Density‐functional theory calculations indicate that iron‐doped cobalt molybdate accelerates the conversion of tripropylamine (TPrA) into TPrA radicals, forming a signal gradient with the cobalt molybdate catalytic region and thereby further enhancing the dimensionality of information encryption. Furthermore, a chemical ink‐based ECL sensor was developed for ultra‐sensitive detection of the cancer biomarker CA15‐3, demonstrating the dual potential application in biomedical information security and disease diagnosis.