Magnetic loading of tyrosinase-Fe3O4/mesoporous silica core/shell microspheres for high sensitive electrochemical biosensing

A new protocol is proposed for magnetic loading and sensitive electrochemical detection of phenol via the tyrosinase cross-linked mesoporous magnetic core/shell microspheres. The mesoporous magnetic microspheres, characterized by transmission electron microscopy, N-2 adsorption/desorption isotherms, and magnetic curve displays high capacity for enzyme immobilization and strong magnetism to adhere to the magnetic electrode surface without any additional adhesive reagent. The biosensor exhibits a wide linear response to phenol ranging from 1.0 x 10(-9) to 1.0 x 10(-5) M, a high sensitivity of 78 mu A mM(-1), a low detection limit of 1 nM, and a fast response rate (less than 5 s). The proposed method is simple, rapid, inexpensive and convenient in electrode renewal, which is recommended as a promising experimental platform for wider applications in biosensing. (C) 2010 Elsevier B.V. All rights reserved.