Self-Assembly of Peptide Nanostructures onto an Electrode Surface for Nonenzymatic Oxygen Sensing

Abstract

We report here the fabrication of a biomimetic sensor for direct oxygen reduction; the sensor consists of multicopper oxidases derived from cyclic-tetrameric copper(II) species containing the ligand (4-imidazolyl)ethylene-2-amino-1-ethylpyridine (apyhist) that are self-assembled with L-diphenylalanine micro/nanostructures (FF-MNTs). The [Cu 4 (apyhist) 4 ] 4+ /FF-MNT complex was immobilized onto the surface of a glassy carbon (GC) electrode by poly ion complex formation with a Nafion film. This hybrid membrane allows regular proton transport to a Cu-based molecular oxygen reduction reaction catalyst, and the imidazole group in the imine ligand (apyhist) acts as a local buffer in the vicinity of the O 2 reducing center, thus aiding the catalyst in retaining its selectivity for 4e − / 4H + oxygen reduction reaction. This nanocomposite provided improved sensing characteristics in the electrode interface with respect to the electroactive surface area, the diffusion coefficient, and the electron transfer kinetics. In addition, the hybrid film [Cu 4 (apyhist) 4 ] 4+ /FF-MNT-coated GC electrode was successfully used as an enzymeless electrochemical sensor for the detection of dissolved oxygen in aqueous media at two concentration intervals, viz., 0.2−3.0 mg L −1 and greater than 3.0 mg L −1 , with sensitivities of 25.0 and 80.2 μA L mg −1 cm −2 , respectively, and a detection limit of 0.1 mg L −1 . Evaluated in terms of relative standard deviation, the repeatability of the proposed sensor was less than 9.0% for ten measurements of a solution of 6.5 mg L −1 oxygen. Experimental efforts were conducted to use this proposed platform for O 2 determination with real samples. Results from theoretical investigations using density functional theory support the hypothesis that the [Cu 4 (apyhist) 4 ] 4+ complex can act as the sole source of protons and electrons in the O 2 reduction reaction.

Dynamic Luminescent Biosensors Based on Peptides for Oxygen Determination

“…In a recent electrochemical biosensor, peptide micro/nanostructures are self-assembled with a complex of copper that acts as the oxygen reduction catalyst, immobilized onto a glassy carbon. This biosensor showed a lower detection limit of 0.1 mg l −1 [35]. Most recent optical biosensors based on FRET transducing include a BOD biosensor chip and a ratiometric FRET sensor.…”

Development of a Novel Cu(II) Complex Modified Electrode and a Portable Electrochemical Analyzer for the Determination of Dissolved Oxygen (DO) in Water

“…Gewirth et al recently reported that several Cu(II)-complexes adsorbed on a carbon black electrode can catalyze the electrocatalytic electron reduction of O2 [10]. Sousa et al evaluated the electrochemical response and the stability of a [Cu4(apyhist)4] 4+ complex (apyhist = 2-(1H-imidazol-4-yl)-N-(1-(pyridin-2-yl)ethylidene)ethanamine) for the fabrication of a novel biomimetic oxygen sensor [11].…”

“…The system architecture, modular packaging, and interface electronics of the designed and fabricated is here presented and its characteristics are compared with that of a commercial one for real time monitoring of DO in water. 4 ] 4+ complex (apyhist = 2-(1H-imidazol-4-yl)-N-(1-(pyridin-2-yl)ethylidene)ethanamine) for the fabrication of a novel biomimetic oxygen sensor [11].…”

Fabricação de novas superfícies eletroativas para a fabricação de sensores eletroquímicos para oxigênio

“…A platina (Pt) e outros metais nobres têm sido extensivamente empregados como catalisadores de 4e-na ORR, mas o custo elevado, a escassez e propensão de envenenamento pelo monóxido de carbono, que limita sua vasta aplicação, têm justificado a procura por materiais alternativos eletrocatalíticos. Neste contexto, após a publicação de trabalhos sobre as propriedades de ftalocianinas e porfirinas de cobalto [51], vários outros mediadores moleculares tais como o DNA [52], antraquinona [53,54], azul de polimetileno [55], peptídeos nanoestructurados [56], complexos de cobalto [21,57,58,59,60], ftalocianina tetrassulfonada de ferro (II) e tetra (N-metil-piridil) porfirina de ferro (II) [7], ftalocianina de magnésio (II) [61], níquel Salen [27], vitamina B-12 [62], ABTS-lacase [63], ZnO dopado com RuO2 [64], diamino-o-benzoquinona [65], índigo tetrassulfonato [66]…”

“…e eugenol[67] têm sido estudados.A medição contínua da concentração de oxigênio é essencial em muitos procedimentos médicos e aplicações, processos tecnológicos e de monitoramento e análise ambiental. Vários sensores eletroquímicos à base de mediadores ORR têm sido propostos para a determinação de oxigênio dissolvido em água[41,56,57,64,68,69,70,71,72], mas nenhum deles apresenta robustez adequada, requisito importante para competir com eletrodos de Clark. A título de exemplo, naTabela 1apresentam-se distintos sensores eletroquímicos com informações sobre faixa linear, limite de detecção, método eletroquímico empregado e potencial no qual são feitas as determinações analíticas de O2.…”