Surface Of Magnetic Graphene Oxide Research Articles

Magnetic solid-phase extraction of protein by ionic liquid-coated Fe@graphene oxide

Amino functional dicationic ionic liquid (AFDCIL) was prepared and then coated on the surface of magnetic graphene oxide (GO) as a new magnetic adsorbent (Fe@GO@AFDCIL) for the magnetic solid-phase extraction (MSPE) of protein. The Fe@GO@AFDCIL composite was characterized by vibrating sample magnetometer (VSM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and zeta-potential nanoparticles. The bovine hemoglobin (BHb) was used as the analyte, and the extraction performance of Fe@GO@AFDCIL was investigated in the MSPE procedure. The concentration of BHb in samples was determined by a UV–vis spectrophotometer. A comparative investigation of Fe@GO@AFDCIL composite and traditional IL-coated Fe@GO composites (Fe@GO@IL) exhibited the benefits of Fe@GO@AFDCIL. The adsorbed BHb could be eluted from the Fe@GO@AFDCIL by 4% sodium dodecyl sulfate (SDS) solution. The Fe@GO@AFDCIL exhibited favorable stability which could be reused at least 15 times. Under the optimized condition, the real samples were investigated, which demonstrated that the Fe@GO@AFDCIL was able to be applied in extracting bovine hemoglobin (BHb) from real biological samples.

A label-free multi-functionalized graphene oxide based electrochemiluminscence immunosensor for ultrasensitive and rapid detection of Vibrio parahaemolyticus in seawater and seafood

A label-free electrochemiluminescence (ECL) immunosensor for ultrasensitive and rapid detection of marine pathogenic bacterium Vibrio parahaemolyticus (VP) in seawater and seafood was developed based on multi-functionalized graphene oxide, which was prepared with N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and VP antibody (anti-VP) simultaneously immobilized on the surface of magnetic graphene oxide (nanoFe3O4@GO). ABEI and anti-VP acted as the electrochemiluminophore and the capture device for VP respectively. Good conductivity and two-dimensional structure of the nanoFe3O4@GO enabled all the ABEI, immobilized on GO, electrochemically active and thus improved the detection sensitivity. Under optimal conditions, the ECL intensity decreased with increasing logarithmic concentrations of VP in the range of 10–108CFU/mL, with a detection limit of 5CFU/mL for seawater and 5CFU/g for seafood. This ECL immunosensor showed high specificity, stability and reproducibility for the detection of VP. In addition, the ECL immunosensor has been successfully used to determine the concentration of VP in seawater and seafood rapidly, with a recovery of 94.4–112.0% and RSD 4.1–11.7%. Therefore, the developed immunosensor shows great prospect for practical application.

Magnetic graphene oxide modified with choline chloride-based deep eutectic solvent for the solid-phase extraction of protein

Four kinds of green deep eutectic solvents (DESs) based on choline chloride (ChCl) have been synthesized and coated on the surface of magnetic graphene oxide (Fe3O4@GO) to form Fe3O4@GO-DES for the magnetic solid-phase extraction of protein. X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FESEM) and thermal gravimetric analysis (TGA) were employed to characterize Fe3O4@GO-DES, and the results indicated the successful preparation of Fe3O4@GO-DES. The UV–vis spectrophotometer was used to measure the concentration of protein after extraction. Single factor experiments proved that the extraction amount was influenced by the types of DESs, solution temperature, solution ionic strength, extraction time, protein concentration and the amount of Fe3O4@GO-DES. Comparison of Fe3O4@GO and Fe3O4@GO-DES was carried out by extracting bovine serum albumin, ovalbumin, bovine hemoglobin and lysozyme. The experimental results showed that the proposed Fe3O4@GO-DES performs better than Fe3O4@GO in the extraction of acidic protein. Desorption of protein was carried out by eluting the solid extractant with 0.005molL−1 Na2HPO4 contained 1molL−1 NaCl. The obtained elution efficiency was about 90.9%. Attributed to the convenient magnetic separation, the solid extractant could be easily recycled.

A one-step electrochemiluminescence immunosensor preparation for ultrasensitive detection of carbohydrate antigen 19-9 based on multi-functionalized graphene oxide

A one-step electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of carbohydrate antigen 19-9 (CA19-9) was developed based on multi-functionalized graphene oxide (GO), which was prepared with N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and CA19-9 antibody (anti-CA19-9) chemically bound to the surface of magnetic GO (nanoFe3O4@GO). ABEI and anti-CA19-9 acted as the electrochemiluminophore and the capture device for CA19-9 respectively. NanoFe3O4@GO enabled all the ABEI immobilized molecules electrochemically active due to its good conductivity, and brought multi-functionalized GO attracted on the surface of magnetic glass carbon electrode through magnetism. Thus the ECL immunosensor could be prepared through a one-step process that facilitates ultrasensitive detection of CA19-9. Under optimal conditions, the ECL intensity of the immunosensor decreased proportionally to the logarithmic concentrations of CA19-9 in the range of 0.001–5U/mL with a detection limit of 0.0005U/mL. This one-step ECL immunosensor showed good performance in specificity, stability, reproducibility, regeneration and application. It opened a new avenue to apply multi-functionalized bionanomaterials in ECL immunoassay.

Rapid Removal and Separation of Iron(II) and Manganese(II) from Micropolluted Water Using Magnetic Graphene Oxide

A novel two-dimensional carbon-based magnetic nanomaterial, magnetic graphene oxide (MGO), was prepared and then used as an efficient adsorbent. MGO showed rapid and complete removal of iron(II) (Fe) and manganese(II) (Mn) from micropolluted water bodies over a wide pH range. After saturated adsorption, MGO could be rapidly separated from water under an external magnetic field. Results of the adsorption equilibrium study indicated that the adsorption of Fe and Mn by MGO took place via monolayer heterogeneous and spontaneous processes resulting from the heterogeneity of the MGO surface as well as from the electrostatic interactions between surface acidic groups of MGO and metal ions. In addition, both the Fe and Mn uptake of MGO was very slightly affected by NaCl, although it decreased with increased humic acid in solutions. In an Fe/Mn binary aqueous system, both metal ions can be efficiently removed at low concentrations, but MGO showed preferential adsorption of Fe in a concentrated aqueous mixture. The adsorption behavior in the binary system was due to different affinities of surface oxygen-containing functional groups on MGO to Fe and Mn. Finally, unlike traditional approaches in recycling and reusing an adsorbent, the Fe- and Mn-loaded MGO can be directly applied as a new adsorbent to achieve the efficient removal of fluoride from aqueous solutions.

Controlled synthesis of pentachlorophenol-imprinted polymers on the surface of magnetic graphene oxide for highly selective adsorption

A novel, magnetic GO-modified with molecularly imprinted polymer (MGO@MIP) was controllably synthesized and shown to exhibit excellent adsorption performance towards PCP.