An Electrochemical Evaluation of Novel Ferrocene Derivatives for Glutamate and Liver Biomarker Biosensing

Here, we present an evaluation of two new monosubstituted ferrocene (Fc) derivatives, 3-(1H-pyrrol-1-yl)propanamidoferrocene and 1-hydroxy-2-[2-(thiophen-3-yl)-ethylamino]ethylferrocene, as glutamate oxidase mediators, together with their preparation and characterisation. Taking into consideration the influence of the electronic effects of substituents on the redox potentials of the Fc species, two candidates with pyrrole or thiophene moieties were proposed for investigation. Film studies involved potential sweeping in the presence of pyrrole or 3,4-ethylenedioxythiophene monomers resulting in stable electroactive films with % signal loss upon cycling ranging from 1 to 7.82% and surface coverage (Γ) 0.47–1.15 × 10−9 mol/cm2 for films formed under optimal conditions. Construction of a glutamate oxidase modified electrode resulted in second-generation biosensing with the aid of both cyclic voltammetry and hydrodynamic amperometry, resulting in glutamate sensitivity of 0.86–1.28 μA/mM and Km (app) values over the range 3.67–5.01 mM. A follow-up enzyme assay for liver biomarker γ-glutamyl transpeptidase realised unmediated and mediated measurement establishing reaction and incubation time investigations and a realising response over <100 U/L γ-glutamyl transpeptidase with a sensitivity of 5 nA/UL−1.

Programmed topographical features generated on command in confined electroactive films

This work describes a method to create dynamic pre-programmed surface textures by an alternating electric field on coatings that consist of a silicon oxide reinforced viscoelastic siloxane network. Finite element...

The electron as a probe to measure the thickness distributions of electroactive films

A theoretical model combined to an experimental study shows that the morphology of electron conducting films can be quantified directly from the analysis of cyclic voltammetry data.

Formation and application of electrochemically active cross-linked triarylamine–siloxane films using the Piers–Rubinsztajn reaction

Cross-linked triarylamine–siloxane hybrid thin film have been formed using Piers–Rubinsztajn chemistry. Key to this approach was the use of a ring-opening reaction to prevent the evolution of volatile small molecules. A representative cyclic ether containing biphenyl triarylamine compound was synthesized and on ring-opening was shown to form a smooth, glassy, and electroactive films by cross-linking with tetrakis(dimethylsiloxy)silane (QM*4). It was found that the films were electrochemically active with low glass transition temperatures. Cross-linked films were incorporated into organic light emitting diodes (OLEDs) under various conditions and functionality within OLEDs was confirmed. Finally, the resistance of the system to dissolution (orthogonality) was considered by casting F8T2, a p-type emitting polymer, from solution on top of the cross-linked film, which formed a working OLED.

Electrochemical Behavior of Electroactive PVS/PANI Films Containing Chemically Modified Cellulose

Electroactive films containing cellulose modified with cationic and anionic groups were prepared with polyaniline (PANI) and poly (vinyl sulfonic acid) (PVS). The modifications were performed with (aminomethyl) pyridine (AMP), ethylenediamine (EDA), buthylenediamine (BN), bis-(aminopropyl) piperazine (APP), maleic anhydride (MA), and phosphate PO43- groups. The films were prepared using the layer-by-layer (LbL) technique, utilizing dispersed cellulose in a PANI solution forming the PVS/PANI system (cationic or anionic cellulose). Films of unmodified microcrystalline cellulose (MC) were also prepared for comparison. The films were characterized by cyclic voltammetry. The electrochemical responses of PANI present in the film, especially in terms of current density and redox potential, were found to be influenced by the modification of the cellulose.