Grafting of Diazonium Salts on Surfaces: Application to Biosensors

Abstract

This review is divided into two parts; the first one summarizes the main features of surface modification by diazonium salts with a focus on most recent advances, while the second part deals with diazonium-based biosensors including small molecules of biological interest, proteins, and nucleic acids.

Keywords: biosensor; diazonium; surface modification.

Scheme 1

Electrografting of diazonium salts.

Figure 1

Cyclic voltammograms (scans 1–3) at fluorine tin oxide (FTO) electrode in HCl 0.5 M + 2 × 10⁻³ M 4-aminobenzoic acid + 2.2 × 10⁻³ M NaNO₂. Scan rate of 0.1 V∙s⁻¹. By courtesy of C. Cannizzo.

Figure 2

SEM image of (A) Au nanotriangles after irradiation with visible light in the presence of 4-[1-(2-bisthienyl)]benzenediazonium, (B) nanodiscs modified with visible light (Ba) with carboxyphenyl films grafted along the Y-direction, (Bb) additional hydroxyethyl phenyl films along the X-axis, (Bc) Schematic presentation of the modified nanodisk. From References [23,24,25], with permission of the American Chemical Society (ACS) and the Royal Chemical Society, respectively.

Figure 3

Single-walled carbon nanotube (SWCNT) modified with polyethyleneglycol (PEG) and mannose groups. From Reference [31] with permission of Elsevier.

Figure 4

Arrays of SWCNTs bonded by reaction of diazonium salts.

Figure 5

Binding graphene sheets using a bis-diazonium salt. From Reference [37] with permission of Wiley.

Figure 6

Molecular junction with carbon nanoribbons: (a) t-butylnitrite in ACN; (b) electrochemical reduction. PPF: pyrolyzed photoresist film, a very flat carbon surface, eC: electron-beam deposited carbon. From Reference [40] with permission of ACS.

Figure 7

Modification of a MoS₂ sheet by 4-nitrobenzenediazonium (Mo violet, S orange). From Reference [42] with permission of the Royal Society of Chemistry.

Figure 8

Gold nanoparticles covalently attached to a screen-printed electrode (SPE) and modified with caboxyphenyl groups for sensing metal ions. From Reference [49] with permission from Elsevier.

Figure 9

A schematic presentation of a film obtained from diazonium salts.

Figure 10

(A,B) STM (scanning tunneling microscopy) images of films obtained on highly oriented pyrolytic graphite (HOPG) after spontaneous grafting of (A) 4-nitrobenzenediazonium and (B) 3,5-bis-tert-butylbenzenediazonium salts. (C) AFM (atomic force microscopy) image of a monolayer obtained from 4-nitrobiphenyldiazonium salt (l = 1.21 nm) on PPF, a near-atomically flat carbon; in the black square, the layer was erased by AFM scratching. From References [57,58] with permission of the American Chemical Society.

Figure 11

Adsorption and electrografting of long-chain benzenediazonium tetrafluoroborate on graphene. From Reference [63] with permission of the American Chemical Society.

Figure 12

Detection of glucose by attaching glucose oxidase (GOx) to a glassy carbon surface. Catalytic scheme for the electro-catalyzed oxidation of its reduced form (GOxH₂).

Figure 13

Biosensor of glucose based on the direct electron transfer to the of GOx flavine adenine dinucleotide (FAD) co-enzyme through a molecular wire.

Figure 14

Attachment of glucose oxidase through graphene oxide and gold nanoparticles. From Reference [76] with permission of the Royal Chemical Society.

Figure 15

A schematic presentation of the surface chemistry used for immobilization anti-okadaic acid (OA) monoclonal antibody on an SPE electrode, and Nyquist plots of 1 mM [Fe(CN)₆]^4−/3− for (a) bare SPE, (b) SPE modified by 4-carboxybenzenediazonium, (c) and an antibody, (d) in the presence of 10 µg/L ochratoxin. The insert is the equivalent electric circuit applied to fit the impedance spectroscopy. From Reference [98] with permission of Elsevier.

Figure 16

Electrografting of an immunoglobulin G (IgG) on an array of screen-printed electrodes. From Reference [104] with permission of Wiley.

Figure 17

A sandwich immunoassay for the detection of rheumatoid factor. From Reference [104] with permission of Wiley.

Figure 18

Cyclic voltammetry of the diazonium salts of 4-aminophenyl phosphorylcholine (PPC), 4-(4-aminophenyl) butyric acid (PBA), and their mixture on an indium tin oxide (ITO) electrode. From Reference [117] with permission of the American Chemical Society.

Figure 19

Immunoassay of tumor necrosis factor α (TNF-α) factor based on a mixed antifouling platform. From Reference [117] with permission of the American Chemical Society.

Figure 20

Transistor for the detection of odors (“e-nose”). From Reference [112] with permission of the American Chemical Society.

Figure 21

DNA sensors for human papillomavirus oncogene detection. From Reference [130] with permission of the American Chemical Society.

Figure 22

Detection of normal and melanoma-associated cell secretome by SERS (surface-enhanced Raman spectroscopy).