title: Stabilization of glucose oxidase in alginate microspheres with photoreactive diazoresin nanofilm coatings.
abstract: The nanoassembly and photo-crosslinking of diazo-resin (DAR) coatings on small alginate microspheres for stable enzyme entrapment is described. Multilayer nanofilms of DAR with poly(styrene sulfonate) (PSS) were used in an effort to stabilize the encapsulation of glucose oxidase enzyme for biosensor applications. The activity and physical encapsulation of the trapped enzyme were measured over 24 weeks to compare the effectiveness of nanofilm coatings and crosslinking for stabilization. Uncoated spheres exhibited rapid loss of activity, retaining only 20% of initial activity after one week, and a dramatic reduction in effective activity over 24 weeks, whereas the uncrosslinked and crosslinked {DAR/PSS}-coated spheres retained more than 50% of their initial activity after 4 weeks, which remained stable even after 24 weeks for the two and three bilayer films. Nanofilms comprising more polyelectrolyte layers maintained higher overall activity compared to films of the same composition but fewer layers, and crosslinking the films increased retention of activity over uncrosslinked films after 24 weeks. These findings demonstrate that enzyme immobilization and stabilization can be achieved by using simple modifications to the layer-by-layer self-assembly technique.
authors.affiliation: Biomedical Engineering Program and Institute for Micromanufacturing, Louisiana Tech University, 911 Hergot Avenue, P.O. Box 10137, Ruston, Louisiana 71272, USA. rsr004@latech.edu
authors.forename: Rohit
authors.initials: R
authors.lastname: Srivastava
authors.forename: J Quincy
authors.initials: JQ
authors.lastname: Brown
authors.forename: Huiguang
authors.initials: H
authors.lastname: Zhu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McShane
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000032:analysis / Q000737:chemistry*; D001391:Azo Compounds / Q000032:analysis / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D005949:Glucose Oxidase / Q000032:analysis / Q000737:chemistry*; D020723:Glucuronic Acid / Q000032:analysis / Q000737:chemistry; D006603:Hexuronic Acids / Q000032:analysis / Q000737:chemistry; D008422:Materials Testing; D008863:Microspheres; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry*; D010316:Particle Size; D010777:Photochemistry / Q000379:methods*; D011485:Protein Binding
chemical_list: D000464:Alginates; D001391:Azo Compounds; D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; C504851:diazoresin; D020723:Glucuronic Acid; D005949:Glucose Oxidase