Non-enzymatic Determination of L-Proline Amino Acid in Unprocessed Human Plasma Sample Using Hybrid of Graphene Quantum Dots Decorated with Gold Nanoparticles and Poly Cysteine: A Novel Signal Amplification Strategy

Abstract

An innovative electrochemical interface for quantitation of L-proline (L-Pro) based on ternary amplification strategy was fabricated. In this work, gold nanoparticles prepared by soft template methodology were immobilized onto green and biocompatible nanocomposite containing poly as a conductive matrix and graphene quantum dots as the amplification element. Therefore, a novel multilayer film based on poly-L-cysteine, graphene quantum dots (GQDs), and gold nanoparticles (GNPs) was exploited to develop a highly sensitive electrochemical sensor for the detection of L-Pro. Fully electrochemical methodology was used to prepare a new transducer on a glassy carbon electrode, which provided a high surface area towards sensitive detection of L-Pro. The prepared electrode was employed for the detection of L-Pro. Under optimized conditions, the calibration curve for L-Pro concentration was linear in 0.5 nM - 10 mM with a low limit of quantification of 0.1 nM. The practical analytical utility of the modified electrode was illustrated by determination of L-Pro in unprocessed human plasma samples.

Sensitive monitoring of taurine biomarker in unprocessed human plasma samples using a novel nanocomposite based on poly(aspartic acid) functionalized by graphene quantum dots

“…It has been reported that immobilization of P(ASP) film on GCE could improve the electrochemical reaction kinetic of some species such as dopamine, hydroquinone, and vitamins, but the report focusing on the detection of taurine did not appear. We suppose a possible action mechanism as follows: Having been polymerized in NaOH, l ‐ASP was oxidized and formed a polymer conductance film on the surface of GCE …”

Carbon Nanodots in Electrochemical Sensors and Biosensors: A Review

“…A list of applications of CNDs based electrochemical sensors for amino acids sensing and important DNA/RNA bases. Target Method Linear range Detection limit Refs. MIB/Au/ERGQD/GCE GSH DPV 0.03-1300.0 μM 9 nM [240] CTAB-AuNRs-GQDs/GCE GSH amperometry 0.5-7 μM 0.23 μM [241] GQDs/β-CD/GCE TRP isomers DPV -- [237] N-CDs/β-CD/GCE TRP isomers DPV [242] Fe FF/GQDs)/CS/CTAB TRP enantiomers DPV -- [244] GQDs-CS/GCE TRP enantiomers DPV -- [245] GQDs-TA/GCE TRP enantiomers DPV -- [246] NH β-CD-GQD/GCE L-Cys DPV 0.01-2 mM - [255] PPy/GQDs@PB/GF L-Cys amperometry 0.2-1000 μM 0.15 μM [236] rCDs-CS/PB/ITO L-Cys amperometry -- [256] Poly-L-cysteine/GQD/GNPs/GCE L-P DPV 0.5 nM-10 mM 0.1 nM [257] Poly(aspartic acid)-GQDs/GCE Taurine DPV -0.001 mM [258] AgNPs/GQD/GCE G A an electrochemical redox probe in order to bind to double stranded DNA (dsDNA) specifically. [284] In another example, an aptasensor is designed for hepatitis C virus (HCV) core antigen measurement.…”

Voltammetric Determination of Amino Acids Based on the Measurement of Reduction Prepeak of Quinone Caused by Surplus Acid after Neutralization

“…However, because most amino acids are electrochemically less active, derivatization methods are also used in HPLC with electrochemical detection (HPLC-ECD) [17]. In the other methods, enzyme-immobilized or chemically modified electrodes for voltammetry have been developed to determine a specific amino acid [18][19][20]. Although these electroanalytical methods allow for the sensitive and selective determination of amino acids, they require complicated procedures such as derivatization with electroactive reagents and the preparation and maintenance of modified electrodes.…”

“…Amino acid analysis is an important technique in many pharmaceutical, medical, chemical, food research, and industrial areas [1][2][3]. Thus far, various analytical methods have been proposed to determine amino acids, including high-performance liquid chromatography, capillary electrophoresis, enzyme assay, and chemical sensors [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Usually, because of the weak light-absorptive property of amino acids, pre-or post-column derivatization with an appropriate labeling reagent is performed for determining amino acids with sensitivity and selectivity in HPLC with UV detection (HPLC-UV) and fluorescence detection (HPLC-FL) systems [9,10].…”