An Enzyme‐Free Amperometric Sensor Based on Self‐Assembling Ferrocene‐Conjugated Oligopeptide for Specific Determination of L‐Arginine

Abstract

Main observation and conclusion An enzyme‐free amperometric sensor based on a heptadecapeptide possessing an electroactive ferrocene (Fc) linker as ferrocene‐Gly‐Gly‐Gly‐Gly‐Phe‐Gly‐His‐Ile‐His‐Glu‐Gly‐Tyr‐Gly‐Gly‐Gly‐Gly‐Lys‐(CH2)4‐dithiocyclopentane self‐assembled on gold substrate was designed and fabricated for specific determination of L‐arginine (L‐Arg). The detection mechanism is based on conformational change of surface‐immobilized peptide induced by the target L‐Arg, which was confirmed via SEM, TEM, AFM, XPS, and SPR studies. The binding affinity and the recognition feasibility of immobilized specific and non‐specific peptides were also assessed using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The proposed method can serve as “signal‐on” sensor for detection of L‐Arg down to 31 pmol/L with broad linear range (0.0001 to 10 μmol/L). Furthermore, the Fc‐conjugated specific peptide sensor was successfully applied to the determination of L‐Arg in pig serums with a recovery rate of 97.5%—106.9%, and its test results are in good agreement with that of chromatographic instrument, evidencing that the oligopeptide‐based sensor can be served as a simple and enzyme‐free biosensing platform towards L‐Arg for future application.

Ammonium nanochelators in conjunction with arginine-specific enzymes in amperometric biosensors for arginine assay

“…As an alternative to enzymatic approaches, chemo-sensors based on the use of electrocatalytic nanomaterials have been proposed. However, although they are sensitive to Arg, the non-enzymatic sensors exhibit low selectivity [ 19 , 27 – 31 ].…”

Dual-Mode Arginine Assay Based on the Conformation Switch of a Ferrocene-Grafted Polypeptide

“…The minimum energies of lysine (Lys) and histidine (His) combined with GSGSFGHIHEGYEGGK are −2.102 and 11.366 kcal/ mol, respectively, significantly higher than that of Arg (−162.19 kal/mol) at a binding site of EG, confirming that the interaction between Arg and the peptide is dominated by the intermolecular force, which can exclude the influence of positive and negative charge adsorption. Furthermore, the P 16 Fc was also compared with the ferrocene-conjugated oligopeptide performed in our lab, 31 a lower free energy indicates that P 16 Fc has a higher binding ability to Arg. These results from MS calculation are consistent with those of the above microstructure morphology studies, further confirming the feasibility of P 16 Fc-AuNPs for colorimetric assay of Arg.…”

Highly sensitive determination of l-glutamic acid in pig serum with an enzyme-free molecularly imprinted polymer on a carbon-nanotube modified electrode

“…25 However, these techniques are limited by expensive instruments, cumbersome sample processing, complicated operation, or low sensitivity, while for the determination of various nitrogen containing small molecules, electrochemical methods with the advantages of fast response, high sensitivity, and simple operation have seen increased interest recently. [26][27][28][29][30][31] Among these reports, L-Glu sensors have been springing up; [32][33][34][35][36] for example, Pasco et al 32 prepared a carbon paste L-Glu sensor based on the L-Glu dehydrogenase complex with a detection limit of 0.3 mmol L −1 , while Liang et al 35 utilized bacteria to solve the problem of enzyme immobilization. Nevertheless, the traditional L-Glu sensors involved L-Glu oxidase (GLOx) or L-Glu dehydrogenase (GLdh), 37,38 which restricted the working conditions and resulted in extra costs.…”