Colorimetric detection of hydrogen peroxide and glucose using the magnetic mesoporous silica nanoparticles

• A magnetic mesoporous silica nanoparticle was synthesized used for H2O2 and glucose detection.
• The magnetic mesoporous silica nanoparticles provide high peroxidase-mimic activity.
• The magnetic mesoporous silica nanoparticles can rival natural enzyme.
• This is a competitive analytical platform for the detection of H2O2 and glucose.

In this work, we synthesized a type of magnetic mesoporous silica nanoparticle (denoted as Fe3O4@MSN) with Fe3O4 as the core and mesoporous silica the shell. The superparamagnetic Fe3O4-core provides high peroxidase-mimic activity and makes the artificial enzymatic system easily recyclable. Furthermore, Fe3O4 nanoparticles are encapsulated in MSN shells to hinder the aggregation and keep them stable even under harsh conditions. Meanwhile, small active molecules are allowed to diffuse in and out of the MSN shells. Based on these functional units, the Fe3O4@MSN as robust nanoreactors can catalyze a self-organized cascade reaction, which includes oxidation of glucose by oxygen to yield gluconic acid and H2O2, and the latter further oxidizes 3,3,5,5-tetramethylbenzidine (TMB) to produce a color change. The Fe3O4@MSN, whose catalytic efficiency was not strongly dependent on pH and temperature, was successfully used for the detection of glucose and showed excellent sensitivity with a detection limit of 0.4×10−5 mol/L. Nevertheless, the assay is also highly selective toward the glucose detection.

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