title: Multilayer enzyme-coupled magnetic nanoparticles as efficient, reusable biocatalysts and biosensors.
abstract: Herein we report the development of a highly active, magnetically retrievable and reusable biocatalyst using multilayer enzyme coupled-magnetic nanoparticles (MNPs) prepared by layer-by-layer assembly using two well-studied enzymes, horseradish peroxidase (HRP) and glucose oxidase (GOX), as a model enzyme system. We show that by combining the use of a biocompatible linker as well as biospecific immobilisation, the first layer enzyme in our HRP(1)-MNP system retains the native activity of the enzyme in solution, and the overall catalytic activity of the multilayer enzyme system, HRP(x)-MNP, increases linearly with the increasing number of enzyme layers. Furthermore, the HRP(x)-MNP system can be conveniently retrieved by using an external magnetic field and reused for 10 consecutive cycles without apparent reduction of catalytic activity. We also report the development of a novel coupled bienzyme, GOX/HRP(x)-MNP, system that can perform bi-enzymatic reactions to couple the colourless GOX-catalyzed reaction to the chromophoric HRP-catalyzed reaction via H(2)O(2) production. This model bienzyme-MNP system can be used for simple, rapid colorimetric quantification of micromolar glucose.
authors.affiliation: School of Chemistry and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Josep
authors.initials: J
authors.lastname: Garcia
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hannah
authors.initials: H
authors.lastname: Taylor
authors.forename: Oscar
authors.initials: O
authors.lastname: Cespedes
authors.forename: Michael E
authors.initials: ME
authors.lastname: Webb
authors.forename: Dejian
authors.initials: D
authors.lastname: Zhou
mesh_terms: D055162:Biocatalysis; D015374:Biosensing Techniques / Q000379:methods*; D019343:Citric Acid / Q000737:chemistry; D003124:Colorimetry / Q000379:methods; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000032:analysis; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D058185:Magnetite Nanoparticles
chemical_list: D004800:Enzymes, Immobilized; D058185:Magnetite Nanoparticles; D019343:Citric Acid; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D005947:Glucose