Silica-Coated Magnetic Iron Oxide Nanoparticles Grafted onto Graphene Oxide for Protein Isolation

Abstract

In this study, silica-coated magnetic iron oxide nanoparticles (MNPs@SiO2) were covalently conjugated onto graphene oxide (GO/MNP@SiO2) for protein isolation. First, MNPs were precisely coated with a silica layer on the surface by using the reverse microemulsion method, followed by incubation with 3-glycidyloxypropyltrimethoxysilane (GPTS) to produce the GPTS-functionalized MNPs@SiO2 (GPTS-coated MNPs@SiO2) that display epoxy groups on the surface. The silica shell on the MNPs was optimized at 300 µL of Igepal®CO-520, 5 mg of MNP, 100 µL of TEOS, 100 µL of NH4OH and 3% of 3-glycidyloxypropyltrimethoxysilane (GPTS). Simultaneously, polyethyleneimine (PEI) was covalently conjugated to GO to enhance the stability of GO in aqueous solutions and create the reaction sites with epoxy groups on the surface of GPTS-coated MNP@SiO2. The ratio of PEI grafted GO and GPTS-coated MNP@SiO2 (GO/MNP ratio) was investigated to produce GO/MNPs@SiO2 with highly saturated magnetization without aggregation. As a result, the GO/MNP ratio of 5 was the best condition to produce the GO/MNP@SiO2 with 9.53 emu/g of saturation superparamagnetization at a magnetic field of 2.0 (T). Finally, the GO/MNPs@SiO2 were used to separate bovine serum albumin (BSA) to investigate its protein isolation ability. The quantity of BSA adsorbed onto 1 mg of GO/MNP@SiO2 increased sharply over time to reach 628 ± 9.3 µg/mg after 15 min, which was 3.5-fold-higher than that of GPTS-coated MNP@SiO2. This result suggests that the GO/MNP@SiO2 nanostructure can be used for protein isolation.

Synthesis and Cytotoxicity Study of Magnetite Nanoparticles Coated with Polyethylene Glycol and Sorafenib–Zinc/Aluminium Layered Double Hydroxide

“…In the last two decades, the great potential of superparamagnetic iron oxide nanoparticles (SPIONs) with their remarkable chemical and physical properties, such as nanoscale structure, magnetic characteristics, relative chemical stability, and biological compatibility, has been proved for nanomedicine applications [ 10 ]. SPIONs are of great importance for researchers in a wide range of applications including for cancer therapy, biotechnology, and drug delivery [ 11 , 12 ].…”

Improved Solvothermal Synthesis of γ-Fe2O3 Magnetic Nanoparticles for SiO2 Coating

“…It was observed that the silica shell thickness ranged from effectively zero to ca. 52 nm, in the latter case accompanied by the formation of bare silica nanoparticles, when the TEOS concentration was varied from 0.01 to 0.5 M [ 53 ]. EDX confirmed the average elemental composition of the MNPs and Sc-MNPs ( Supplementary Materials, Figure S4 ).…”

Fe3O4@SiO2-L-Cu(II): An efficient and easily recoverable catalyst for reducing/degrading environmental pollutants in aqueous medium

“…One of the most useful procedures for preparing heterogeneous nanocatalysts is to immobilize complexes on solid bases like metal and metal oxides. Magnetic iron oxide nanoparticles (MNPs Fe 3 O 4 ) have received a big deal of interest within metal oxide nanoparticles (NPs), probably because of their special applications [24][25][26]. Iron oxides have good magnetic properties compared to other magnetic nanoparticles and, on the other hand, show high stability against degradation [27,28].…”