User:Markopetek/Magnetic nanobeads

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Magnetic nanobeads

Magnetic nanobeads (also known as magnetic nanoparticle clusters, NPCs) are nanocomposite materials exhibiting magnetic properties. They are composed of a number of individual magnetic nanoparticles and have a diameter of 50–200 nanometers.[1] Nanoparticles can be either fused by sillica or embedded in a polymer matrix.


Types of magnetic nanobeads

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Ferrite magnetic nanobeads

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Magnetic nanobeads with narrow size distribution consisting of superparamagnetic oxide nanoparticles (~ 80 maghemite superparamagnetic nanoparticles per bead) coated with a silica shell have several advantages over metallic nanoparticles:

  • Higher chemical stability (crucial for biomedical applications)
  • Narrow size distribution (crucial for biomedical applications)
  • Higher colloidal stability since they do not magnetically agglomerate
  • Magnetic moment can be tuned with the nanoparticle cluster size
  • Retained superparamagnetic properties (independent of the nanoparticle cluster size)
  • Silica surface enables straightforward covalent functionalization

Magnetic polymer nanobeads

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For preparation of magnetic nanobeads several polymers can be used, such as PLGA, PLA[2], dextran[3], chitosan[4], polyethyleneimine and polystyrene. Nanobeads can be prepared by nano-emulsion method, suspension polymerization, precipitation, etc.

Magnetic nanobeads scaffolded by DNA-binding zinc finger proteins

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Biotinylated zinc finger proteins (ZnF) were conjugated to DNA templates, followed by incubation with neutravidin-conjugated nanoparticles. The sequence specificity of ZnF and programmable DNA templates enabled a size-controlled construction of nanoparticle clusters.[5]

Applications

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Nanophotonics

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Superparamagnetic ferrite nanobeads with the size 80 – 150 nanometers form ordered structures along the direction of the external magnetic field with a regular interparticle spacing on the order of hundreds of nanometers resulting in strong diffraction of visible light in suspension.[6] When an external magnetic field is applied to colloidally dispersed nanobeads the particles form one-dimensional chain-like structures that exhibit structural color. If a photocurable medium is used for the suspension of nanobeads the photonic chain structures can also be fixed in a specific area by selective UV exposure.[7]

Medical diagnostics and treatment

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Drug delivery

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Biomedical imaging

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References

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  1. ^ Tadic, Marin; Kralj, Slavko; Jagodic, Marko; Hanzel, Darko; Makovec, Darko (December 2014). "Magnetic properties of novel superparamagnetic iron oxide nanoclusters and their peculiarity under annealing treatment". Applied Surface Science. 322: 255–264. doi:10.1016/j.apsusc.2014.09.181.
  2. ^ Balasubramaniam, Sharavanan; Kayandan, Sanem; Lin, Yin-Nian; Kelly, Deborah F.; House, Michael J.; Woodward, Robert C.; St. Pierre, Timothy G.; Riffle, Judy S.; Davis, Richey M. (18 February 2014). "Toward Design of Magnetic Nanoparticle Clusters Stabilized by Biocompatible Diblock Copolymers for T2-Weighted MRI Contrast". Langmuir. 30 (6): 1580–1587. doi:10.1021/la403591z.
  3. ^ Su, Hongying; Liu, Yanhong; Wang, Dan; Wu, Changqiang; Xia, Chunchao; Gong, Qiyong; Song, Bin; Ai, Hua (January 2013). "Amphiphilic starlike dextran wrapped superparamagnetic iron oxide nanoparticle clsuters as effective magnetic resonance imaging probes". Biomaterials. 34 (4): 1193–1203. doi:10.1016/j.biomaterials.2012.10.056.
  4. ^ Philippova, Olga; Barabanova, Anna; Molchanov, Vyacheslav; Khokhlov, Alexei (April 2011). "Magnetic polymer beads: Recent trends and developments in synthetic design and applications". European Polymer Journal. 47 (4): 542–559. doi:10.1016/j.eurpolymj.2010.11.006.
  5. ^ Ryu, Yiseul; Jin, Zongwen; Lee, Joong-jae; Noh, Seung-hyun; Shin, Tae-Hyun; Jo, Seong-Min; Choi, Joonsung; Park, HyunWook; Cheon, Jinwoo; Kim, Hak-Sung (12 January 2015). "Size-Controlled Construction of Magnetic Nanoparticle Clusters Using DNA-Binding Zinc Finger Protein". Angewandte Chemie International Edition. 54 (3): 923–926. doi:10.1002/anie.201408593.
  6. ^ He, Le; Wang, Mingsheng; Ge, Jianping; Yin, Yadong (18 September 2012). "Magnetic Assembly Route to Colloidal Responsive Photonic Nanostructures". Accounts of Chemical Research. 45 (9): 1431–1440. doi:10.1021/ar200276t.
  7. ^ Kim, Shin-Hyun; Lee, Su Yeon; Yang, Seung-Man; Yi, Gi-Ra (January 2011). "Self-assembled colloidal structures for photonics". NPG Asia Materials. 3 (1): 25–33. doi:10.1038/asiamat.2010.192.
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Category:Nanotechnology Category:Nanomaterials Category:Nanoparticles Category:Magnetism

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