Preparation of Alkanethiolate-Functionalized Core/Shell Fe₃O₄@Au Nanoparticles and Its Interaction with Several Typical Target Molecules

Abstract

This paper reports the synthesis of alkanethiolate-functionalized core/shell Fe 3 O 4 /Au nanoparticles (Fe 3 O 4 @Au NPs) that combine the advantages of core/shell magnetic nanoparticles with self-assembled monolayers (SAMs). The alkanethiolates, having carboxylic acid (COOH) and methyl (CH 3 ) terminal groups, can be easily self-assembled on the Fe 3 O 4 @Au NPs substrates. The surface composition and structure of 11-mercaptoundecanoic acid (11-MUA) and 1-dodecanethiol (11-DDT) SAMs were characterized in detail using energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). To further study the surface properties of the SAMs, hydrophobic, ionic, and nonionic organic compounds were selected as probe molecules. The results indicated that the hydrophobic interaction caused strong retention of analytes, whereas the repulsive electrostatic interaction between the negatively charged 11-MUA SAMs surface and the negatively charged probe molecule would lead to the decrease of adsorption affinity.In the past few years, nanocomposite materials have been subjected to extensive research as the combination of different nanoscale functionalities are capable of endowing the substrate with enhanced properties and thus have great application potentials in various fields. [1][2][3][4][5][6][7][8][9][10][11] The core/shell nanostructure is an ideal composite system that combines the advantages of "core" and "shell" and has shown enhanced physical and chemical properties.The shell layer not only protects the core from oxidation but also provides a platform for surface modification and functionalization. Generally, magnetic materials are the most commonly selected substrates because they can readily be isolated from sample solutions by the application of an external magnetic field. However, magnetic particles suffer from several inherent limitations as they are likely to aggregate and lose magnetic properties when applied in complex environmental and biological systems. 11 Up to now, most of the research works focus on the preparation of Fe 3 O 4 @Au magnetite nanoparticles and there are only a limited number of literatures about its surface modification capabilities and its practical application. 13,14 Self-assembled monolayers (SAMs) of alkanethiolates on gold surfaces have been extensively studied and widely applied in

Preparation of carbon coated Fe3O4 nanoparticles and their application for solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples

“…This result indicates that it is the carbon layer that responsible for the effective adsorption of PAHs on the magnetic Fe 3 O 4 /C sorbents. The required dosage of Fe 3 O 4 /C sorbents is not only far less than some traditional SPE sorbents, such as graphitized carbon blacks, C 8 or C 18 bonded silica [22,[33][34][35][36], but also less than previous reported nanomaterial SPE sorbents [1][2][3]5,[7][8][9][10][11]15], which may result from the large surface areas of Fe 3 O 4 /C sorbents and strong adsorption ability of carbon materials. In the following experiment, 50 mg Fe 3 O 4 /C nanoparticle sorbents are applied to assure complete adsorption of analytes.…”

“…In order to overcome these disadvantages, various magnetic nanoparticle SPE sorbents have been developed in recent years [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. We have developed a novel SPE method based on mixed hemimicelle modified magnetic nanoparticles [7][8][9].…”

Preparation of Well-Dispersed Gold/Magnetite Nanoparticles Embedded on Cellulose Nanocrystals for Efficient Immobilization of Papain Enzyme

“…In particular, Au nanoparticles (AuNPs) are promising materials for protecting Fe 3 O 4 nanoparticles due to their simple reductive preparation, reliable chemical stability, biocompatibility, and versatility in surface modification. 8 Fe 3 O 4 /Au composites display different structures: core/shell Fe 3 O 4 /Au nanomaterials, 8,9 dumbbell-like Au−Fe 3 O 4 nanoparticles, 10 and covalent attachment of AuNPs onto colloidal Fe 3 O 4 . 1 Robust cellulose nanocrystals (CNCs) with biocompatibility, high crystallinity and mechanical tensile have been fostered in a myriad of applications including enzyme immobilization, 11 drug delivery, 12 and biomedical applications.…”

Biocompatible phosphatidylcholine bilayer coated on magnetic nanoparticles and their application in the extraction of several polycyclic aromatic hydrocarbons from environmental water and milk samples

“…Traditional SPE method involves passing samples completely through cartridges filled with sorbents, and is therefore time consuming and labor intensive, especially for large volume of samples. In order to overcome these disadvantages, a magnetic SPE method has been developed and applied to bioseparation and chemical analyses by many research groups [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In this method, paramagnetic sorbents are dispersed in solution to adsorb the targets and then collected by a magnet for elution, which greatly simplifies the SPE procedure.…”

“…Various magnetic sorbents have been successfully synthesized for sample pretreatment. Our groups have developed mixed hemimicelle [1][2][3][4] and octadecyl (C 18 ) [5,6] functionalized magnetic nanoparticles as sorbents for extraction of target compounds. Magnetic nanoparticles coated with hemimicelles of alkyl carboxylates are used to extract polycyclic aromatic hydrocarbons (PAHs) from environmental water samples, and surfactant-free extracts are obtained due to the strong chemical bonding between alkyl carboxylates and magnetite [16].…”