At present, a host of high-sensitivity and selective tumor marker detection methods play a central role in various research fields and assay platforms. Here, a method for DNA cross-linked hydrogel-capped magnetic core-shell structure mesoporous silica nanoparticles (Fe3O4@nSiO2@mSiO2) based on target stimulus was proposed. Specifically, Fe3O4@nSiO2@mSiO2 nanoparticles with nucleic acid promoter units were prepared. The promoter induces the predesigned modified polyacrylamide DNA strand to carry out hybridization chain reaction on the surface of Fe3O4@nSiO2@mSiO2 nanoparticles, forming a hydrogel coating on the surface of Fe3O4@nSiO2@mSiO2 nanoparticles. Under the stimulation of adenosine, Fe3O4@nSiO2@mSiO2 released the signal molecule luminol. Simultaneously, the MIL-101（Fe）material, a signal amplification molecule, was released from the DNA hydrogel. Compared with the traditional gated mesoporous silica system, the DNA hydrogel-coated Fe3O4@nSiO2@mSiO2 is not easy to leak and has a higher loading capacity. In addition, the optical background of DNA hydrogels is low, combined with MOFs materials, even about 1.4 × 10-10 M adenosine can be detected in this biosensor. Based on the combination of DNA hydrogels, MOFs conjugates and gating systems, the construction of biosensors will be more eye-catching, which will expand new ideas for biosensor platform manufacturing.
Keywords: Adenosine; Chemiluminescence; DNA hydrogels; Magnetic mesoporous silica nanoparticles; Metal organic framework.
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