Enzyme immobilisation on self-organised nanopatterned electrode surfaces

Abstract

A new method is described for immobilisation of enzymes on polymer-coated Pt islands. These islands are deposited on top of a SAM-covered Au(111) electrode by a combination of electroless and electrochemical deposition, which allows for a variation of island size and distance between the islands. Here we describe the immobilisation of pyranose-2-oxidase (P2Ox) and the catalytic response to D-glucose on such a nanopatterned surface, which provides optimum access to the active centres of the enzyme.

Pt-based drugs: the spotlight will be on proteins

“…Moving even further from the pharmacological field, platinumprotein interactions can now find applications in very different fields. Recent examples are the use of platinum-protein complexes to realize a novel self-assembled organometallic material endowed with unique chemico-physical properties, 64 to produce structured surfaces functionalized with enzymes for electroenzymatic measurements 65 or biosensors for quantitative protein detection 66 ending up with the use of platinum complexes in the design of selective artificial metalloproteases. 67 Despite these appealing technical applications, it is worth to conclude this overview with a different perspective in medicinal chemistry.…”

Hydrogen Peroxide Oxidation Reaction on a 4-Mercaptopyridine Self-Assembled Monolayer on Au(111) Metallized by Platinum Nanoislands

“…The question of whether Au or the Pt islands provide the active sites for the HPOR has not been addressed by Kolb and co-workers [1,2]. A single metallization step was used and it was assumed that the Pt islands are catalytically active.…”

“…About one decade ago, Dieter Kolb and co-workers developed an electrochemical enzymatic glucose sensor based on pyranose oxidase immobilized on a Pt-metallized self-assembled monolayer (SAM) on Au(111) [1,2]. Electrochemically deposited Pt nanoislands of monoatomic height were used as pedestals on which enzyme molecules were wired via poly-allylamine as a linking agent.…”

“…It was assumed that the Pt islands are electrocatalytically active towards the oxidation of hydrogen peroxide (HP) (Fig. 1) generated by pyranose oxidase during the enzymatic glucose oxidation [1,2]. Amperometric measurements indeed showed a noticeable stepwise increase of the oxidation current after successive addition of glucose rendering the assumption of catalytic activity of the Pt islands towards the HP oxidation reaction (HPOR) plausible since Pt is wellknown to be an efficient HPOR catalyst.…”

Nanopatterned Bulk Metallic Glass Biosensors

“…Increased effective surface area in turn enables greater amounts of enzyme to be attached directly to the electrode, which consequently may translate to increased sensitivity to changes in blood glucose levels. Heterogeneous surface area enhancements incorporated as additional elements to glucose biosensors have demonstrated the potential for improved biosensing, − as has increased electrode surface roughness via texturing. , However, integration of nanoscale structures also poses challenges, which may limit access to the additional surface area, such as stiction, clumping, and increased electrical interfacial resistance. , The formation of nanotopography onto a planar electrode structure also results in a mechanical interface, which poses challenges related to the robustness of the interfacial adhesion strength and therefore causes device reliability concerns. ,, Reliability concerns are also a factor for nanotopography that is nonuniform and highly variable; complex fabrication and testing processes requiring controlled environments also lead to issues . Biocompatibility and safety of surface area-enhanced electrodes is also a critical consideration.…”