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

Abstract

In this work, three different aqueous solutions containing imidazole-based ILs with different alkyl chain lengths ([Cnmim]Br, n = 2, 6, 12) were adopted as the medium for the synthesis of ionic liquid-polypyrrole (IL-PPy) composites. Herein, the ILs undertook the roles of the pyrrole solvent, the media for emulsion polymerization of PPy and PPy dopants, respectively. The electrochemical performances of the three IL-PPy composites on a glassy carbon electrode (GCE) were investigated by electrochemical experiments, which indicated that [C12mim]Br-PPy (C12-PPy) composites displayed better electrochemical performance due to their larger surface area and firmer immobilization on the GCE. Further, C12-PPy/GCE were decorated with Au microparticles by electrodeposition that can not only increase the conductivity, but also immobilize sufficient biomolecules on the electrode. Then, the obtained C12-PPy-Au/GCE with outstanding electrochemical performance was employed as a horseradish peroxidase (HRP) immobilization platform to fabricate a novel C12-PPy-Au-HRP/GCE biosensor for H2O2 detection. The results showed that the prepared C12-PPy-Au-HRP/GCE biosensor exhibited high sensitivity, fast response, and a wide detection range as well as low detection limit towards H2O2. This work not only provides an outstanding biomolecule immobilization matrix for the fabrication of highly sensitive biosensors, but also advances the understanding of the roles of ILs in improving the electrochemical performance of biosensors.

Advances in the Use of Conducting Polymers for Healthcare Monitoring

“…The synergy of [C12mim]Br, PPy, and Au microparticles establishes an optimized platform for enzyme immobilization, proving to be an effective approach for fabricating highly sensitive biosensors. This work not only presents an advanced biomolecular immobilization matrix for biosensor fabrication with heightened sensitivity but also highlights the potential application of ionic liquids in CP synthesis [176]. In addition, research on the manufacture of PPy nanotubes and their use as electrodes has been conducted, achieving a maximum conductivity of 30.4 S/cm for a diameter of 95 nm [177,178].…”

Recent Advances in Ionic Liquids in Biomedicine

“…The analytes that these electrochemical sensors aim to detect range from biomarkers to therapeutics to omnipresent organic molecules. [ 219 , 220 , 221 , 222 , 223 , 224 , 225 , 226 , 227 , 228 , 229 , 230 , 231 , 232 , 233 , 234 , 235 , 236 ] As mentioned previously, imidazolium and cholinium‐based ionic liquids have been widely used in biomedicine, which holds true for biosensors. Choline dihydrogen phosphate and 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIM[BF 4 ]) coated electrodes with immobilized antibodies were used to detect cortisol and interleukin‐6 in human sweat.…”

Ionic Liquid‐Based Polymer Nanocomposites for Sensors, Energy, Biomedicine, and Environmental Applications: Roadmap to the Future

“…The synthesized C 12 –PPy–Au–HRP/GCE based biosensor has an excellent electrochemical activity for detecting H 2 O 2 . [ 102 ] An IL‐based polymer composite based on cholesterol oxidase (Chox) enzyme acts as a biosensor. It has an outstanding performance for the cholesterol of a less quantity of 0.5 to 5 m m having excellent sensitivity, less responding time, and more stable repeatability.…”