Facile and scalable synthesis of a novel rigid artificial superoxide dismutase based on modified hollow mesoporous silica microspheres

A novel metallosalen complex, named Mn-(bis(salicylaldehyde)-3,4-Diaminobenzoic acid), with superoxide scavenging activity was prepared from manganese(III) acetate dehydrate and bis(salicylaldehyde)-3,4-Diaminobenzoic acid in ethanol. We found that the novel complex has a higher superoxide scavenging activity than traditional complex, named n-(bis(salicylaldehyde)ethylenediamine), without the carboxy, the catalytic process was studied and explained. Hollow silica microspheres (HSMs) that mimics superoxide dismutase activity has been developed by using the HSMs modified with the novel metallosalen complex through the esterification between the carboxy and silanol. The property and superoxide dismutase activity of the metallosalen-modified HSMs were investigated. These novel rigid metallosalen-modified HSMs possess excellent superoxide dismutase activity and it can be easily immobilized to fabricate biomimetic sensor or other catalytic unit/receptor, it solves many practical problems such as easy recovery and repeat utilization. An application test of this novel rigid artificial SOD was performed by fabricating a novel biomimetic sensor to determine superoxide based on mesoporous hollow silica microspheres receptor and rhodanine chemiluminescence detector. In addition, the metallosalen can be replaced by other active centers to mimic novel kind of enzymes and immobilized in/on other devices to establish novel biomimetic sensors.