PotM: Functionalized Superparamagnetic Iron Oxide Nanoparticles

Published on 29.01.2025

SPIO (superparamagnetic iron oxide), SPIONs (superparamagnetic iron oxide nanoparticles), IONPs (iron oxide nanoparticles) - read about their advantages and fields of applications!

PotM: Functionalized Superparamagnetic Iron Oxide Nanoparticles

Superparamagnetism was discovered by Louis Néel in 1949 during studies on fired clay and lava. His work helped to understand the phenomenon and paved the way for the use of superparamagnetic iron oxide (nano-)particles, often abbreviated as SPIOs, SPIONs or IONPs, in many applications. For his ground-breaking work in material science, Néel was awarded the Nobel Prize in Physics in 1970.

A characteristic of superparamagnetic materials is that they are attracted by magnets while they are not permanently magnetized themselves, i.e., they behave naïve as soon as the external magnetic field is removed. The magnetite (Fe3O4, iron(II,III) oxide) particles of SPIOs show this behavior when they are very small and contain only one magnetic domain. Depending on your needs and desired applications, the particles are grafted with different functional groups via propylsilanone moieties or, in the case of carboxylates, via phosphoryl linkers.

 


Different functionalization patterns available for the superparamagnetic iron oxide nanoparticles offered by Iris Biotech. Reactive moieties include chloroalkyl, aminoalkyl, azido, tretrazine, ethylaminoalkyl, propionyl, hexanoyl, thioalkyl, oxirane (epoxide), and maleimidyl residues. The nanoparticles are available as dispersions (NPL product codes) and as powder solids (NPP product codes).

 

Our SPIO nanoparticles are characterized by a narrow dispersity range of 11-17 nm with 0.5-25 functional groups per nm2 (depending on the functionalization), this corresponds to about 400-23000 reactive sites per bead, resulting in a capacity of about 0.05-4 mmol/g. The carboxy-functionalized SPIOs have a capacity of 12-25 reactive sites per nm2, or 4500-22500 groups per bead, equivalent to 1.9-4.2 mmol/g. All SPIO products are available as powder solid and as dispersion with a content of 5 mg/mL. The specifications for each product are listed on the respective product page in our webshop. 

SPIOs are an attractive alternative to chromatography and centrifugation as they require only a little investment in hardware: While in suspension, chemical reactions may be carried out on the surface of the iron oxide nanoparticles. When a magnetic field (e.g., from a strong neodymium magnet or a solenoid) is brought close to the reaction vessel, the particles are attracted, precipitate and may be isolated quickly. This allows for fast, easy, and efficient recovery and cleaning as well as reduced process time, solvent waste, and costs. Furthermore, experiments and assays with SPIOs may be parallelized in miniature formats, like, e.g., 96-well microplates, using arrays of multiple magnets. In ELISAs, a higher ligand density may be achieved on magnetic beads, allowing for shorter incubation times and increased sensitivity. 

For immunoprecipitations and the isolation of antibodies, SPIO particles may be covalently coated with Protein A or Protein G. Streptavidin may be used to bind biotinylated peptides and proteins. Furthermore, functionalized SPIOs may serve as dendrimer-like support to construct multivalent systems, e.g., for drug delivery, which can provide a high ligand density and have a slower clearance.

Immobilized enzymes frequently possess increased stability at higher temperatures, an extended pH range, and sometimes even have higher activity. For immobilized trypsin, stability is increased due to reduced autolysis. An industrial application of SPIO-conjugated enzymes is the removal of lactose from milk with immobilized lactase. Pollutants and side products from chemical reactions may be removed with affinity ligands. 

Another useful property of SPIO is that it modifies the nuclear spin of bound water molecules, which can be used to enhance contrast in MRI imaging. When magnetic particles are conjugated with antibodies, they can be used for diagnostics and targeted therapies. By applying frequencies between 50 and 500 kHz and magnetic fields of 10 to 50 mT, heat (typically 41 to 46 °C) can be generated at the tumor site and thermal apoptosis can be induced. In this way, malignant tissue which is not easily accessible to surgery, such as glioblastomas and insulinomas, can be destroyed. 

Furthermore, the iron oxide core of SPIOs is biodegradable and is dissolved in the lysosomes over time. Amino-modified iron oxide nanoparticles have been found to potentiate ferroptosis by lysosomal iron release. Moreover, it was demonstrated that SPIOs can act as nanofertilizers in mg/mL concentrations. DNA-coated magnetite nanoparticles have been used for the transfection of eukaryotic cells. 

 

→ You need more information or have a specific question? Get in contact! 

→ Interested in this topic? Stay tuned! We will soon report about frequently asked questions related to functionalized superparamagnetic iron oxide nanoparticles.

 

References:

Superparamagnetic Iron Oxide Nanoparticles for Immunotherapy of Cancers through Macrophages and Magnetic Hyperthermia; A. M. M. Dias, A. Courteau, P.-S. Bellaye, E. Kohli, A. Oudot, P. E. Doulain, C. Petitot, P.-M. Walker, R. Decréau, B. Collin; Pharmaceutics 2022; 14: 2388. https://doi.org/10.3390/pharmaceutics14112388 

Surface modified iron-oxide based engineered nanomaterials for hyperthermia therapy of cancer cells; Mehak, R. P. Thummer, L. M. Pandey; Biotechnol. Genet. Eng. Rev. 2023; 39(2): 1187-1233. https://doi.org/10.1080/02648725.2023.2169370 

Interference-free and high precision biosensor based on surface enhanced Raman spectroscopy integrated with surface molecularly imprinted polymer technology for tumor biomarker detection in human blood; X. Lin, Y. Wang, L. Wang, Y. Lu, J. Li, D. Lu, T. Zhou, Z. Huang, J. Huang, H. Huang, S. Qiu, R. Chen, D. Lin, S. Feng; Biosens. Bioelectron. 2019; 143: 111599. https://doi.org/10.1016/j.bios.2019.111599

SPIONs: Superparamagnetic iron oxide-based nanoparticles for the delivery of microRNAi-therapeutics in cancer; G. Kara, B. Ozpolat; Biomed. Microdevices 2024; 36(1): 16. https://doi.org/10.1007/s10544-024-00698-y 

Amino-modified IONPs potentiates ferroptotic cell death due to the release of Fe ion in the lysosome; Z. Qi, X. Huang, J. Jing, W. Feng, M. Xu, L. Yan, M. Gao, S. Liu, X.-F. Yu; J. Environ. Sci. (China) 2025; 150: 1-13. https://doi.org/10.1016/j.jes.2024.01.034 

Nanofertilizers for enhancing food production: A case study on microgreens enrichment using superparamagnetic iron oxide nanoparticles (SPIONs); A. Coelho, A. A. Cavalari, P. Haddad, A. Nogueira do Nascimento; Food Chem. 2025; 463(Pt3): 141364. https://doi.org/10.1016/j.foodchem.2024.141364 

Banana fruit (Musa sp.) DNA-magnetite nanoparticles: Synthesis, characterization, and biocompatibility assays on normal and cancerous cells; D. Arregui-Almeida, M. Coronel, K. Analuisa, C. Bastidas-Caldes, S. Guerrero, M. Torres, A. Aluisa, A. Debut, W. Brämer-Escamilla, F. Pilaquinga; PLoS One 2024; 19(10): e0311927. https://doi.org/10.1371/journal.pone.0311927

Theranostic Application of Mixed Gold and Superparamagnetic Iron Oxide Nanoparticle Micelles in Glioblastoma Multiforme; L. Sun, D. Y. Joh, A. Al-Zaki, M. Stangl, S. Murty, J. J. Davis., B. C. Baumann, M. Alonso-Basanta, G. D. Kaol, A. Tsourkas, J. F. Dorsey. J. Biomed. Nanotechnol. 2016; 12(2): 347-356. https://doi.org/10.1166/jbn.2016.2173 

Functionalized Magnetic Nanoparticles for Theranostic Applications; Editors: M. Pandey, K. Deshmukh, C. M. Hussain; Scrivener Publishing LLC 2025. https://doi.org/10.1002/9781394172917 

Tailored functionalization of iron oxide nanoparticles for MRI, drug delivery, magnetic separation and immobilization of biosubstances; K. Hola, Z. Markova, G. Zoppellaro, J. Tucek, R. Zboril; Biotechnol. Adv. 2015; 33(67 Pt 2): 1162-1176. https://doi.org/10.1016/j.biotechadv.2015.02.003 

Verwandte Produkte
    1. Fe3O4-NH2 (nanoparticle powder)
      Fe3O4-NH2 (nanoparticle powder)

      Art-Nr.: NPP1000

      Partikelgröße: 11-17 nm

      Ab 800,00 €

    2. Fe3O4-NH2 (nanoparticle dispersion)
      Fe3O4-NH2 (nanoparticle dispersion)

      Art-Nr.: NPL1000

      Partikelgröße: 11-17 nm

      Ab 100,00 €

    3. Fe3O4-Cl (nanoparticle powder)
      Fe3O4-Cl (nanoparticle powder)

      Art-Nr.: NPP1010

      Partikelgröße: 11-17 nm

      Ab 720,00 €

    4. Fe3O4-Cl (nanoparticle dispersion)
      Fe3O4-Cl (nanoparticle dispersion)

      Art-Nr.: NPL1010

      Partikelgröße: 11-17 nm

      Ab 100,00 €

    5. Fe3O4-SH (nanoparticle powder)
      Fe3O4-SH (nanoparticle powder)

      Art-Nr.: NPP1020

      Partikelgröße: 11-17 nm

      Ab 820,00 €

    6. Fe3O4-SH (nanoparticle dispersion)
      Fe3O4-SH (nanoparticle dispersion)

      Art-Nr.: NPL1020

      Partikelgröße: 11-17 nm

      Ab 100,00 €

    7. Fe3O4-Propionate (nanoparticle powder)
      Fe3O4-Propionate (nanoparticle powder)

      Art-Nr.: NPP1030

      Partikelgröße: 11-17 nm

      Ab 1.060,00 €

    8. Fe3O4-Propionate (nanoparticle dispersion)
      Fe3O4-Propionate (nanoparticle dispersion)

      Art-Nr.: NPL1030

      Partikelgröße: 11-17 nm

      Ab 140,00 €

    9. Fe3O4-N3 (nanoparticle powder)
      Fe3O4-N3 (nanoparticle powder)

      Art-Nr.: NPP1040

      Partikelgröße: 11-17 nm

      Ab 1.090,00 €

    10. Fe3O4-N3 (nanoparticle dispersion)
      Fe3O4-N3 (nanoparticle dispersion)

      Art-Nr.: NPL1040

      Partikelgröße: 11-17 nm

      Ab 130,00 €

    11. Fe3O4-Tetrazine (nanoparticle powder)
      Fe3O4-Tetrazine (nanoparticle powder)

      Art-Nr.: NPP1050

      Partikelgröße: 11-17 nm

      Ab 2.750,00 €

    12. Fe3O4-Tetrazine (nanoparticle dispersion)
      Fe3O4-Tetrazine (nanoparticle dispersion)

      Art-Nr.: NPL1050

      Partikelgröße: 11-17 nm

      Ab 230,00 €

    13. Fe3O4-Mal (nanoparticle powder)
      Fe3O4-Mal (nanoparticle powder)

      Art-Nr.: NPP1060

      Partikelgröße: 11-17 nm

      Ab 1.780,00 €

    14. Fe3O4-Mal (nanoparticle dispersion)
      Fe3O4-Mal (nanoparticle dispersion)

      Art-Nr.: NPL1060

      Partikelgröße: 11-17 nm

      Ab 180,00 €

    15. Fe3O4-Epoxy (nanoparticle powder)
      Fe3O4-Epoxy (nanoparticle powder)

      Art-Nr.: NPP1070

      Partikelgröße: 11-17 nm

      Ab 790,00 €

    16. Fe3O4-Epoxy (nanoparticle dispersion)
      Fe3O4-Epoxy (nanoparticle dispersion)

      Art-Nr.: NPL1070

      Partikelgröße: 11-17 nm

      Ab 100,00 €

    17. Fe3O4-Diamine (nanoparticle powder)
      Fe3O4-Diamine (nanoparticle powder)

      Art-Nr.: NPP1080

      Partikelgröße: 11-17 nm

      Ab 800,00 €

    18. Fe3O4-Diamine (nanoparticle dispersion)
      Fe3O4-Diamine (nanoparticle dispersion)

      Art-Nr.: NPL1080

      Partikelgröße: 11-17 nm

      Ab 100,00 €

    19. Fe3O4-Hexanoate (nanoparticle powder)
      Fe3O4-Hexanoate (nanoparticle powder)

      Art-Nr.: NPP1090

      Partikelgröße: 11-17 nm

      Ab 3.790,00 €

    20. Fe3O4-Hexanoate (nanoparticle dispersion)
      Fe3O4-Hexanoate (nanoparticle dispersion)

      Art-Nr.: NPL1090

      Partikelgröße: 11-17 nm

      Ab 300,00 €