Mussel-inspired surface capping and pore filling to confer mesoporous silica with high loading and enhanced stability of enzyme

Abstract

Based on mussel-inspired chemistry, a facile method was developed to prevent the leaching of enzyme from mesoporous silica supports, thus achieving high loading and enhanced stability of immobilized enzyme. More specifically, two approaches to enzyme-containing polydopamine (PDA)-silica hybrid materials were explored. One was to directly dip the enzyme-loaded bimodal mesoporous silica (BMS, 2–3 nm and 10–50 nm) spheres into the dopamine solution, acquiring enzyme-loaded PDA-filled BMS. Another was to first deposit a polyelectrolytes layer onto outer surface of enzyme-loaded BMS spheres and then dip into dopamine solution, acquiring enzyme-loaded PDA-capped BMS. Using catalase (CAT) as model enzyme, both CAT-loaded PDA-filled and PDA-capped BMS spheres displayed high loading and enhanced stability due to effective suppression of the enzyme leakage and drastic preservation of the catalytic activity. For example, ∼90 mg CAT could be loaded in 1 g of BMS after dopamine treatment with less than 5% loss in activity under rigorous stirring for 6 h, as compared to over 60% loss in activity for CAT adsorbed on BMS without treatment. CAT loaded in PDA-filled or PDA-capped BMS spheres showed 61.7% and 78.1% of relative activities, respectively.