Chemiluminescence sensing of adenosine using DNA cross-linked hydrogel-capped magnetic mesoporous silica...

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.