Immunomagnetic Separation of Microorganisms with Iron Oxide Nanoparticles

Background: Magnetic nanoparticles (MNPs) are becoming more important as carriers, because of their large specific surface area and easy separability. They are increasingly used in enzyme technology, diagnostics, and drug delivery. Major results: For the directed and almost irreversible immobilization of proteins on MNPs, we have developed a new selective (His-Arg) 4 peptide-tag, that binds fusion proteins directly from an E. coli cell lysate to non-functionalized, low-cost MNPs. Using the immobilization of an ene-reductase as an example, we could demonstrate that the fusion with this tag increases thermostability without reducing overall activity (ER w/o tag: t 1/2 = 3.7 h, (HR) 4-ER: t 1/2 = 9.9 h). Immobilization by adsorption in Tris buffer resulted in very high enzyme loads with approx. 380 mg g-1 and 67% residual activity. The immobilization on the MNPs allowed a fast concentration, buffer exchange, and reuse. While about 50% of the activity was lost after the first reuse, we were able to show that the activity did not decrease further and was stable for another nine cycles. Conclusion: According to our studies, our tag highly works for any kind of immobilization on MNPs and holds the potential for enzyme immobilizations as well as for drug delivery and sensors. K E Y W O R D S affinity tag, ene-reductase, enzyme immobilization, iron oxides, magnetic nanoparticles 1 INTRODUCTION Magnetic nanoparticles are used in all kinds of applications, such as enzyme immobilization, bioimaging, biosensors, drug delivery, enrichment of bacteria, and many more. [1-5] The high specific surface areas Abbreviations: (HR) 4 , dipeptide histidine-arginine repeated four times; AEX, anion exchange chromatography; Arg, arginine; BCA, bicinchoninic acid; ER, ene-reductase; ER w/o tag, ene-reductase without a tag; FMN, flavin mononucleotide; GFP, green fluorescent protein; His, histidine; HPLC, high-performance liquid chromatography; IMAC, immobilized metal affinity chromatography; Lys, lysine; MNPB, bound proteins on magnetic nanoparticles; MNPs, magnetic nanoparticles; MNPS, supernatant of magnetic nanoparticles after magnetic separation; MNPW, wash supernatant of magnetic nanoparticles after magnetic separation; NADH, nicotinamide adenine dinucleotide; NADPH, nicotinamide adenine dinucleotide phosphate; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SEC, size exclusion chromatography; TBS, Tris-buffered saline This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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“…The MNPs were synthesized by co‐precipitation of iron salts with sodium hydroxide following the protocol of Thomas et al. [ 28 ]…”

Section: Methodsmentioning

confidence: 99%

Selective ene‐reductase immobilization to magnetic nanoparticles through a novel affinity tag

Zanker

Ahmad

Son

et al. 2020

Biotechnology Journal

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“…FTIR is one of the analytical techniques that are used to reveal the functional groups present in the sample and also to determine the microcrystalline nature of the particles. In Figure 2, the FTIR spectra reveal the three characteristic peaks at 552 cm −1 , 645 cm −1 , and 990 cm −1 which are attributed to the Fe-O bond [50]. The band at 1636 cm −1 and 3410 cm −1 is attributed to the hydroxyl group of a water molecule or ferric hydroxides present in the samples [51].…”

Section: Fourier Transform Infrared (Ftir) and Raman Spectroscopy Of mentioning

confidence: 98%

“…to the Fe-O bond [50]. The band at 1636 cm -1 and 3410 cm -1 is attributed to the hydroxyl group of a water molecule or ferric hydroxides and vibration modes.…”

Section: Fourier Transform Infrared (Ftir) and Raman Spectroscopy Of mentioning

confidence: 98%

Synthesis and Characterization of Amorphous Iron Oxide Nanoparticles by the Sonochemical Method and Their Application for the Remediation of Heavy Metals from Wastewater

et al. 2020

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Nanoparticles have gained huge attention in the last decade due to their applications in electronics, medicine, and environmental clean-up. Iron oxide nanoparticles (IONPs) are widely used for the wastewater treatment due to their recyclable nature and easy manipulation by an external magnetic field. Here, in the present research work, iron oxide nanoparticles were synthesized by the sonochemical method by using precursors of ferrous sulfate and ferric chloride at 70 °C for one hour in an ultrasonicator. The synthesized iron oxide nanoparticles were characterized by diffraction light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), electron diffraction spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM). The FTIR analysis exhibits characteristic absorption bands of IONPs at 400–800 cm−1, while the Raman spectra showed three characteristic bands at 273, 675, and 1379 cm−1 for the synthesized IONPs. The XRD data revealed three major intensity peaks at two theta, 33°, 35°, and 64° which indicated the presence of maghemite and magnetite phase. The size of the spherical shaped IONPs was varying from 9–70 nm with an average size of 38.9 nm while the size of cuboidal shaped particle size was in microns. The purity of the synthesized IONPs was confirmed by the EDS attached to the FESEM, which clearly show sharp peaks for Fe and O, while the magnetic behavior of the IONPs was confirmed by the VSM measurement and the magnetization was 2.43 emu/g. The batch adsorption study of lead (Pb) and chromium (Cr) from 20% fly ash aqueous solutions was carried out by using 0.6 mg/100 mL IONPs, which exhibited maximum removal efficiency i.e., 97.96% and 82.8% for Pb2+ and Cr ions, respectively. The fly ash are being used in making cements, tiles, bricks, bio fertilizers etc., where the presence of fly ash is undesired property which has to be either removed or will be brought up to the value of acceptable level in the fly ash. Therefore, the synthesized IONPs, can be applied in the elimination of heavy metals and other undesired elements from fly ash with a short period of time. Moreover, the IONPs that have been used as a nanoadsorbent can be recovered from the reaction mixture by applying an external magnetic field that can be recycled and reused. Therefore, this study can be effective in all the fly ash-based industries for elimination of the undesired elements, while recyclability and reusable nature of IONPs will make the whole adsorption or elimination process much economical.

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“…The saturation magnetization is only slightly lower than pure bare iron oxide nanoparticles and the shape of the hysteresis curve is similar (Fig. 2) [38,49,50]. Hence, surface layer and core composition of SPIONs and cCNT-SPIONs composites are similar [50].…”

Section: Iron Oxide Nanoparticles Synthesized By Co-precipitation In mentioning

confidence: 78%

Iron Oxide Nanoparticle - Multiwall Carbon Nanotube Composite Materials for Batch or Chromatographic Biomolecule Separation

Schwaminger

Brammen

Zunhammer

et al. 2020

Preprint

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Carbon-based materials are the spearhead of research in multiple fields of nanotechnology. Moreover, their role as stationary phase in chromatography is gaining relevance. We investigate a hybrid material consisting of multiwall carbon nanotubes (CNTs) and superparamagnetic iron oxide nanoparticles (SPIONs) towards its use as a mixed-mode chromatography material. The idea is to immobilize the ion exchange material iron oxide on CNTs as a stable matrix for chromatography processes without a 2 significant pressure drop. Iron oxide nanoparticles are synthesized and used to decorate the CNTs via a co-precipitation route. They bind to the walls of oxidized CNTs, thereby enabling to magnetically separate the hybrid material. This hybrid material is investigated with transmission electron microscopy, magnetometry, X-ray diffraction, X-ray photoelectron and Raman spectroscopy. Moreover, we determine its specific surface area and its wetting behavior. We also demonstrate its applicability as chromatography material for amino acid retention, describing the adsorption and desorption of different amino acids in a complex porous system surrounded by aqueous media. Thus, this material can be used as chromatographic matrix and as a magnetic batch adsorbent material due to the iron oxide nanoparticles. Our work contributes to current research on composite materials. Such materials are necessary for developing novel industrial applications or improving the performance of established processes.

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Immunomagnetic Separation of Microorganisms with Iron Oxide Nanoparticles

Cited by 33 publications

References 50 publications

Selective ene‐reductase immobilization to magnetic nanoparticles through a novel affinity tag

Selective ene‐reductase immobilization to magnetic nanoparticles through a novel affinity tag

Synthesis and Characterization of Amorphous Iron Oxide Nanoparticles by the Sonochemical Method and Their Application for the Remediation of Heavy Metals from Wastewater

Iron Oxide Nanoparticle - Multiwall Carbon Nanotube Composite Materials for Batch or Chromatographic Biomolecule Separation

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