Layer-by-layer electrostatic deposition of biomolecules on surfaces for molecular recognition, redox mediation and signal generation

Abstract

Layer-by-layer supramolecular structures composed of alternate layers of negatively charged enzymes and cationic redox polyelectrolyte have been assembled. Glucose oxidase (GOx), lactate oxidase (LOx) and soybean peroxidase (SBP) have been electrically wired to the underlying electrode by means of poly(allylamine) with [Os(bpy)2 ClPyCOH]c ovalently attached (PAAÈOs) in organized structures with high spatial resolution. Biotinylated glucose oxidase has also been used to assemble step-by-step on antibiotin goat immunoglobulin (IgG) layers and the enzyme was electrically wired by PAAÈOs. These spatially organized multilayers with mono-and bienzymatic schemes can work efficiently in molecular recognition, redox mediation and generation of an electrical signal. The concentration of redox mediator integrated into the multilayers, obtained from the voltammetric charge and an estimation of the layer thickness, exceeds by 100-fold the amount of deposited enzyme assessed by quartz crystal microbalance. Di †erences in GOx electrical wiring efficiency have been detected with the di †erent assembling strategies. The surface concentration of electrically wired enzyme represents a small proportion of all the enzyme molecules present in the multilayers which can be oxidized by the soluble mediator PyCOOH]Cl. This proportion, as well as the rate of [Os(bpy) 2 Cl FADH 2 oxidation by PAAÈOs, increases with the number of electrically wired enzyme layers and with the spatial accessibility of the Os moiety to the enzyme active center.

Polyelectrolyte Complex Membranes for Immobilizing Biomolecules, and Their Applications to Bio-analysis

“…Moreover, the advanced function of polyelectrolyte complexes involves the retention of a certain extent of mobility in PIC membranes. In bound-type enzyme mediator systems, an osmium complex is mainly used as the mediator, 70,71 whereas ferrocene particles, [72][73][74][75][76] methylene blue, 77 Cu(II) ion, 78 and toluidine blue 79 can be used as the mediator in the entrapped-type system.…”

SERS in PAH-Os and gold nanoparticle self-assembled multilayers

“…7,11,23 The substrates consist of gold films ͑ϳ150 nm thick͒ evaporated on Si͑001͒ wafers. The adsorption time for each component, thiol, polymer, and gold nanoparticles were determined by a preliminary quartzcrystal microbalance study.…”

Enzymatic Biofuel Cells—Fabrication of Enzyme Electrodes

“…Glucose oxidase (GOx), lactate oxidase (LOx) and soybean peroxidase (SBP) have been electrically wired to the underlying electrode by means of poly(allylamine) with [Os(bpy) 2 ClPyCOH]+ covalently attached (PAA-Os) in organized structures with high spatial resolution. The concentration of redox mediator integrated into the multilayers, obtained from the voltammetric charge and an estimation of the layer thickness, exceeds by 100-fold the amount of deposited enzyme assessed by quartz crystal microbalance [59]. An electrode was fabricated by alternate layer-by-layer deposition of periodate-oxidized glucose oxidase (GOx) and poly(allylamine) (PAA) by Zhang et al [32].…”