An Amperometric Acetylcholinesterase Sensor Based on the Bio-templated Synthesis of Hierarchical Mesoporous Bioactive Glass Microspheres

Abstract

This work describes the synthesis of three-dimensional hollow hierarchical mesoporous bioactive glass (HMBG) microspheres based on Herba leonuri pollen grains via a hydrothermal method. The HMBG microspheres perfectly copied the hierarchical porous structure and inner hollow structure constituting the double-layer surface of the natural Herba leonuri pollen grains. This structural mimicry of the pollen grains resulted in a higher degree of adsorption of acetylcholinesterase (AChE) on HMBG microspheres in comparison with mesoporous bioactive glass. Subsequently, an amperometric biosensor for the detection of Malathion was fabricated by immobilizing AChE onto an HMBG microspheres-modified carbon paste electrode. The biosensor response exhibited two good linear ranges during an incubation time of 10 min in the malathion concentration ranges of 0.02–50 ppb and 50–600 ppb, with a detection limit of 0.0135 ppb (S/N = 3). Overall, the prepared enzymatic biosensor showed high sensitivity in the rapid detection of Malathion and could be applied to detect pesticide residues in vegetable matter. An amperometric acetylcholinesterase (AChE) sensor was successfully prepared using HMBG microspheres as the carrier for adsorption of enzyme. The HMBG microspheres perfectly copied the hierarchical porous structure and inner hollow structure with a double-layer surface of the natural Herba leonuri pollen grains. The hybrid structures resulted in more AChE adsorption and protected the catalytic activity of AChE effectively, which made the sensor sensitive and stable.