Polyferrocenyl Polycyclosiloxane/Gold Nanoparticles: An Efficient Electrocatalytic Platform for Immobilization and Direct Electrochemistry of HRP

Abstract

Sensitivity and enzyme stability are the main targets in the biosensors improvement. This work achieves both by means of the combination of two efficient electrocatalysts: ferrocene and gold nanoparticles (AuNPs). The AuNPs were electrodeposited onto a polyferrocenyl polycyclosiloxane polymer (FPP) in order to obtain an electrocatalytic framework for the covalent immobilization and direct electrochemistry of horseradish peroxidase (HRP). The developed surface is like that obtained with graphene modified electrodes, with very high specific area. The kinetic study of electrodes modified with and without HRP showed that the FPP/AuNPs system greatly improves other more complex systems based on the direct HRP electro-reduction by AuNPs, allowing the use of lower measuring potentials, with improved sensitivity, wider linear ranges and lower detection limits. The obtained apparent Michaelis-Menten constant, KM,app, was 0.32 mM, significantly lower than the intrinsic KM, revealing the very high enzymatic efficiency of the developed device. The HRP/AuNPs/FPP/Pt electrode was used as biosensor for hydrogen peroxide with two wide linear ranges of 0–200 μM and 200–6800 μM, and a high sensitivity of 685.71 μA mM−1 cm−2, a low detection limit of 50 nM and long-term stability. The new device has been successfully used too as for the determination of organic hydroperoxides.

Ionic Liquid-Polypyrrole-Gold Composites as Enhanced Enzyme Immobilization Platforms for Hydrogen Peroxide Sensing

“…Therefore, the construction of immobilized enzyme layers that can accelerate the electron transfer as well as retain their specific bioactivity is highly desired [8]. So far, a large number of nanomaterials have been employed as substrate materials to immobilize enzymes for the construction of electrochemical enzyme sensors, such as metal nanoparticles [9], carbon nanomaterials [10], graphene [11] and conducting polymers [12]. Among these substrate materials, conducting polymers have intrinsic superiority in the electrochemical field owing to their good conductivity, easy modification and biocompatibility [13].…”

Thiolated DAB Dendrimer-Gold Nanoparticles Self-Assembled Monolayer as Covalent Support for Direct Electrochemistry of HRP and Sensing Applications

“…HRP is widely used in hydrogen peroxide amperometric biosensors of 2 nd and 3 rd [1][2][3][4][5] generations because the possibility of stablish direct electrochemistry with the electrode material. The H 2 O 2 is a by-product of a lot of oxidase enzymatic reactions, consequently has great interest for sensing in pharmaceutical or industrial processes as well as in clinical, food or environmental analysis.…”

Electron Flow in Large Metallomacromolecules and Electronic Switching of Nanoparticle Stabilization: Click Ferrocenyl Dentromers that Reduce AuIII to Au Nanoparticles

“…[2] Ferrocenyl-terminated dendrimers are among the most precise metal-containing polymers and have attracted the attention of the organometallic, electrochemistry,a nd macromolecular communities for more than two decades. [3][4][5] Thisi nterest is due to both their reversible cyclic voltammetry and the useful redox and functional chemistry of ferrocene, [6] which have applications as catalysts, [7] nanoreactors, [8] sensors, [9] electrochemical mediators, [10] molecular electrodes, [11] and biomedical vectors. [12] In spite of many electrochemical studies,h owev-er,f errocenyl-terminated dendrimers have not been used so far as redox agents for chemical transformations.…”