TiO2 nanotube array-modified electrodes for L-cysteine biosensing: experimental and density-functional theory study.
Nanotechnology
; 31(50): 505501, 2020 Dec 11.
Article
em En
| MEDLINE
| ID: mdl-33006325
ABSTRACT
We report a non-enzymatic facile method for the detection of L-cysteine (L-Cyst) using free-standing TiO2 nanotube (TNT) array-modified glassy carbon electrodes (GCEs). Self-organized, highly ordered, and vertically oriented TNT arrays were fabricated by anodization of titanium sheets in ethylene glycol-based electrolyte. Detailed electrochemical measurements were performed and it was found that modified GCE exhibited high current compared to the pristine counterpart. The high current of the modified electrode was attributed to the high surface area and enhanced electrocatalytic activities of the TNTs toward the L-Cyst oxidation. Under the optimum conditions, the modified electrode exhibited a high sensitivity of â¼1.68 µA mM-1 cm-2 with a low detection limit of â¼0.1 mM. The fabricated electrode was found to be sensitive to pH and electrolyte temperature. The real sample analysis of the proposed method showed a decent recovery toward L-Cyst addition in human blood serum. Furthermore, the density-funcational theory (DFT) analysis revealed that TNTs have greater affinity toward L-Cyst, having stronger binding distance after its adsorption. The higher negative E ads values suggested a stable and chemisorption nature. The density of states results show that the E gap of TNTs is significantly reduced after L-Cyst adsorption. The modified GCE showed excellent selectivity, enhanced stability, and fast response, which make TNTs a promising candidate for the enzyme-free detection of other biological analytes.
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MEDLINE
Idioma:
En
Revista:
Nanotechnology
Ano de publicação:
2020
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Article
País de afiliação:
Paquistão