A polydopamine-coated mesoporous nanocomposite with robust affinity to horseradish peroxidase based on catecholic adhesion

Providing robust affinity for HRP to avoid leakage and loss of activity, and improve resistance to external environments is essential to fabricate HRP-functionalized surface applied in various biosensors. Here, a facile universal polydopamine coating is prepared via dopamine self-polymerization process on mesoporous magnetic nanocrystal clusters. It is found that the adsorption of mesoporous nanocomposites for horseradish peroxidase (HRP) is pH dependent, and the high binding capacity toward HRP is mainly based on catecholic anchoring at pH ≤ 8. The interaction is stable even when exposed to a wide range of pH from 4 to 11 with negligible leakage rate below 7%. The immobilized HRP can effectively resist the influence of surrounding environments such as acid, alkali, high salt and high temperature on the catalytic activity. The nanocomposites are further used to measure glucose in human serum with good reliability.