Gold Nanomaterials-Based Electrochemical Sensors and Biosensors for Phenolic Antioxidants Detection: Recent Advances

Abstract

Antioxidants play a central role in the development and production of food, cosmetics, and pharmaceuticals, to reduce oxidative processes in the human body. Among them, phenolic antioxidants are considered even more efficient than other antioxidants. They are divided into natural and synthetic. The natural antioxidants are generally found in plants and their synthetic counterparts are generally added as preventing agents of lipid oxidation during the processing and storage of fats, oils, and lipid-containing foods: All of them can exhibit different effects on human health, which are not always beneficial. Because of their relevant bioactivity and importance in several sectors, such as agro-food, pharmaceutical, and cosmetic, it is crucial to have fast and reliable analysis Rmethods available. In this review, different examples of gold nanomaterial-based electrochemical (bio)sensors used for the rapid and selective detection of phenolic compounds are analyzed and discussed, evidencing the important role of gold nanomaterials, and including systems with or without specific recognition elements, such as biomolecules, enzymes, etc. Moreover, a selection of gold nanomaterials involved in the designing of this kind of (bio)sensor is reported and critically analyzed. Finally, advantages, limitations, and potentialities for practical applications of gold nanomaterial-based electrochemical (bio)sensors for detecting phenolic antioxidants are discussed.

Keywords: electrochemical (bio)sensors; flavonoids; gold nanomaterials; phenolic acids; phenolic antioxidants; stilbenes; synthetic antioxidants.

Figure 1

Electrochemical sensor applications of Au and Au-based nanomaterials. Reprinted with permission from [39] Copyright 2020, Elsevier.

Figure 2

(A) Turkevich–Frens method for synthesis of AuNPs via reduction of gold salts in the presence of trisodium citrate; (B) Brust–Schiffrin strategy for two-phase fabrication of small-size AuNPs via reduction of gold salts in the presence of thiol ligands; (C) seed-mediated growth method for AuNPs; (D) green synthesis of non-toxic AuNPs through intra- and extra-cellular biosynthesis in the presence of proteins or cell-free extracts. Reprinted with permission from [40] Copyright 2018 Elsevier.

Figure 3

Schematic illustrations summarizing four major types of Au nanocages derived from the corresponding templates of Ag: A single-crystal cube with sharp corners; a single-crystal cube with truncated corners; a single-crystal octahedron with truncated corners; a polycrystalline, quasi-spherical particle. Reprinted with permission from [51]. Copyright 2010, Wiley.

Figure 4

Schematic representations of the synthesis of alloyed bimetallic nanoparticles considering the silver-gold system. (A) Bottom-up synthesis, leading to alloyed silver-gold nanoparticles after co-reduction. (B) Bottom-up synthesis, leading to silver-gold core-shell nanoparticles (seeded-growth approach). (C) Bottom-up synthesis, leading to hollow gold nanoshells (anodic dissolution of the silver core). (D) Top-down synthesis to prepare alloyed silver-gold nanoparticles starting from a bimetallic alloy by laser ablation. Reprinted with permission from [57]. Copyright 2020, Wiley.

Figure 5

Schematic representation of the synthetic pathways of graphene-AuNPs nanocomposites.

Figure 6

Chemical structure of gallic acid (GA).

Figure 7

Schematic representation of the hydroxycinnamic acids and derivatives considered in this review.

Figure 8

(A) Assembly of Au/NGQDs sensing platform for the photo-electrochemical (PEC) detection of caffeic acid (CA). (B) Schematic illustration of the sensing mechanism. Reprinted from [98].

Figure 9

Illustration of synthesis route for TAPB-DMTP-COFs/AuNPs. Reprinted with permission from [103]. Copyright 2018, Elsevier.

Figure 10

Schematic representation of GCA detection at TAPB-DMTP-COFs/AuNPs/GCE. Reprinted with permission from [103]. Copyright 2018, Elsevier.

Figure 11

Chemical structure of resveratrol (RES).

Figure 12

Structures of flavonoids and their subgroup classification.

Figure 13

General structure of chalcones.

Figure 14

Chemical structure of phloretin (PH).

Figure 15

Schematic illustration of the assembly of A549 cell-based sensor (A) and of the evaluation process of the PH antioxidant capacity (B). Reprinted with permission from [129]. Copyright 2018, Elsevier.

Figure 16

Chemical structure of luteolin (LUT).

Figure 17

Schematic illustration of the synthesis process of AuNFs-BPC and the LUT electrochemical determination. Reprinted with permission from [136]. Copyright 2021, Elsevier.

Figure 18

Chemical structure of myricetin (MYR).

Figure 19

A schematic representation of the electrochemical oxidation of myricetin at the (P₂W₁₈-SnO₂-AuNPs)₃/ITO electrode. Reprinted with permission from [143]. Copyright 2019, Elsevier.

Figure 20

Chemical structure of quercetin (QR).

Figure 21

Schematic illustration of assembling of GODs/AuNPs/GCE and the electrochemical determination of quercetin (QR). Reprinted with permission from [158]. Copyright 2016, Wiley.

Figure 22

Chemical structure of rutin (RT).

Figure 23

Assembliy of ErGO-AuNPs-MOFs/GCE as rutin electrochemical sensor. Reprinted with permission from [168]. Copyright 2021, Elsevier.

Figure 24

Chemical structure of catechin (CAT).

Figure 25

Chemical structure of the most common SPAs.

Figure 26

(a) Schematic representation of the AuNP-WC composite synthesis and of TBHQ oxidation mechanism. SEM images of (b–d) WC and (e–g) AuNP-WC at different magnifications. Reprinted with permission from [194]. Copyright 2021, Elsevier.