Iron nanoparticle

{{Short description |Sub-micrometer iron particles}} {{Nanomat}}

'''Nanoscale iron particles''' are sub-micrometer particles of iron metal.<ref>{{Cite journal |last=Huber |first=Dale L. |date=May 2005 |title=Synthesis, Properties, and Applications of Iron Nanoparticles |url=https://onlinelibrary.wiley.com/doi/10.1002/smll.200500006 |journal=Small |language=en |volume=1 |issue=5 |pages=482–501 |doi=10.1002/smll.200500006 |pmid=17193474 |bibcode=2005Small...1..482H |issn=1613-6810|url-access=subscription }}</ref> Due to their high catalytic activity, permanent magnetic properties, low toxicity, and strong adsorption capacity, iron-based nanoparticles are widely utilized in drug delivery, production of magnetic tapes (e.g., camcorders and backup tapes of computers<ref>{{Cite web |title=Iron Nanoparticles: Properties and Applications |url=https://shop.nanografi.com/blog/iron-nanoparticles-properties-and-applications/#:~:text=Iron%20nanoparticles%20are%20used%20to,needed%20to%20reverse%20the%20magnetization. |access-date=2025-04-12 |website=Nanografi Advanced Materials |language=en}}</ref>), gene therapy, and environmental remediation.<ref name=":0">{{Cite journal |last1=Xu |first1=Weihua |last2=Yang |first2=Ting |last3=Liu |first3=Shaobo |last4=Du |first4=Li |last5=Chen |first5=Qiang |last6=Li |first6=Xin |last7=Dong |first7=Jie |last8=Zhang |first8=Zhuang |last9=Lu |first9=Sihui |last10=Gong |first10=Youzi |last11=Zhou |first11=Liang |last12=Liu |first12=Yunguo |last13=Tan |first13=Xiaofei |date=2022-01-01 |title=Insights into the Synthesis, types and application of iron Nanoparticles: The overlooked significance of environmental effects |journal=Environment International |volume=158 |article-number=106980 |doi=10.1016/j.envint.2021.106980 |bibcode=2022EnInt.15806980X |issn=0160-4120|doi-access=free }}</ref>

== Synthesis == Iron nanoparticles can be synthesized using two primary approaches: top-down and bottom-up methods.<ref name=":1">{{Cite journal |last1=Saif |first1=Sadia |last2=Tahir |first2=Arifa |last3=Chen |first3=Yongsheng |date=November 2016 |title=Green Synthesis of Iron Nanoparticles and Their Environmental Applications and Implications |journal=Nanomaterials |language=en |volume=6 |issue=11 |pages=209 |doi=10.3390/nano6110209 |doi-access=free |issn=2079-4991 |pmc=5245755 |pmid=28335338}}</ref>

=== Top-down Methods === Top-down approaches create nanoparticles by breaking down larger bulk materials into smaller particles, including laser ablation and mechanical grinding.<ref name=":0" />

=== Bottom-up Methods === Bottom-up approaches involve the chemical and biological synthesis of iron nanoparticles from metal precursors (e.g., Fe(II) and Fe(III)).<ref name=":0" /> This method is widely regarded as the most effective and commonly used strategy for nanoparticle preparation.<ref name=":1" /> For example, iron nanoparticles can be chemically prepared by reducing Fe(II) or Fe(III) salts with sodium borohydride in an aqueous medium. This process can be described by the following equations:<ref>{{Cite journal |last1=Wang |first1=Chuan-Bao |last2=Zhang |first2=Wei-xian |date=1997-07-01 |title=Synthesizing Nanoscale Iron Particles for Rapid and Complete Dechlorination of TCE and PCBs |url=https://pubs.acs.org/doi/10.1021/es970039c |journal=Environmental Science & Technology |volume=31 |issue=7 |pages=2154–2156 |doi=10.1021/es970039c |bibcode=1997EnST...31.2154W |issn=0013-936X|url-access=subscription }}</ref><ref>{{Cite journal |last1=Ponder |first1=Sherman M. |last2=Darab |first2=John G. |last3=Mallouk |first3=Thomas E. |date=2000-06-01 |title=Remediation of Cr(VI) and Pb(II) Aqueous Solutions Using Supported, Nanoscale Zero-valent Iron |url=https://pubs.acs.org/doi/10.1021/es9911420 |journal=Environmental Science & Technology |volume=34 |issue=12 |pages=2564–2569 |doi=10.1021/es9911420 |bibcode=2000EnST...34.2564P |issn=0013-936X|url-access=subscription }}</ref>

:4 Fe³⁺ + 3 BH₄⁻ + 9 H₂O → 4 '''Fe⁰'''↓ + 12 H⁺ + 6 H₂ + 3 H₂BO⁻{{spaces|6}}(1)

:4 Fe²⁺ + 3 BH₄⁻ + 9 H₂O → 4 '''Fe⁰'''↓ + 8 H⁺ + 8 H₂ + 3 H₂BO⁻{{spaces|6}}(2)

== Properties == Iron nanoparticles are prone to oxidation when exposed to air and water.<ref name=":0" /> This redox process can occur under both acidic and neutral/basic conditions:<ref>{{Cite journal |last1=Dickinson |first1=Michelle |last2=Scott |first2=Thomas B. |date=2010-06-15 |title=The application of zero-valent iron nanoparticles for the remediation of a uranium-contaminated waste effluent |url=https://linkinghub.elsevier.com/retrieve/pii/S0304389410000932 |journal=Journal of Hazardous Materials |volume=178 |issue=1 |pages=171–179 |doi=10.1016/j.jhazmat.2010.01.060 |pmid=20129731 |bibcode=2010JHzM..178..171D |issn=0304-3894|url-access=subscription }}</ref>

:2 '''Fe⁰''' + 4 H⁺ + O₂ → 2 Fe²⁺ + 2 H₂O{{spaces|6}}(3) :'''Fe⁰''' + 2 H₂O → Fe²⁺ + H₂ + 2 OH⁻{{spaces|6}}(4)

== Application in biomedicine == Iron oxide nanoparticles (IONPs) have widely investigated for applications in biomedicine, including magnetic resonance imaging and cancer therapy via magnetic hyperthermia<ref>{{Cite journal |last1=Espinosa |first1=Ana |last2=Di Corato |first2=Riccardo |last3=Kolosnjaj-Tabi |first3=Jelena |last4=Flaud |first4=Patrice |last5=Pellegrino |first5=Teresa |last6=Wilhelm |first6=Claire |date=2016-02-23 |title=Duality of Iron Oxide Nanoparticles in Cancer Therapy: Amplification of Heating Efficiency by Magnetic Hyperthermia and Photothermal Bimodal Treatment |url=https://pubs.acs.org/doi/full/10.1021/acsnano.5b07249 |journal=ACS Nano |volume=10 |issue=2 |pages=2436–2446 |doi=10.1021/acsnano.5b07249 |pmid=26766814 |bibcode=2016ACSNa..10.2436E |issn=1936-0851|url-access=subscription }}</ref><ref>{{Cite journal |last1=Liu |first1=Jia |last2=Xu |first2=Jie |last3=Zhou |first3=Jun |last4=Zhang |first4=Yu |last5=Guo |first5=Dajing |last6=Wang |first6=Zhigang |date=2017-02-09 |title=Fe3O4-based PLGA nanoparticles as MR contrast agents for the detection of thrombosis |journal=International Journal of Nanomedicine |language=English |volume=12 |pages=1113–1126 |doi=10.2147/IJN.S123228 |doi-access=free |pmc=5310639 |pmid=28223802}}</ref>

In addition to these applications, IONPs exhibit strong antibacterial activity and have been explored for drug and viral vector delivery to target cells.<ref name=":2">{{Cite journal |last1=V. |first1=Gudkov, Sergey |last2=E. |first2=Burmistrov, Dmitriy |last3=A. |first3=Serov, Dmitriy |last4=B. |first4=Rebezov, Maksim |last5=A. |first5=Semenova, Anastasia |last6=B. |first6=Lisitsyn, Andrey |date=July 2021 |title=Do Iron Oxide Nanoparticles Have Significant Antibacterial Properties? |url=https://www.mdpi.com/2079-6382/10/7/884 |journal=Antibiotics |language=en |volume=10 |issue=7 |doi=10.3390/antibiotic |doi-broken-date=1 July 2025 |doi-access=free |issn=2079-6382 |archive-url=https://web.archive.org/web/20250304223852/https://www.mdpi.com/2079-6382/10/7/884 |archive-date=2025-03-04 |access-date=2025-04-12 |url-status=live }}</ref> Known microorganisms susceptible to the toxic effects of IONPs include Gram-negative bacteria (e.g., ''Escherichia coli'' and ''Klebsiella'' sp.) and Gram-positive bacteria (e.g., ''Bacillus'' sp. and ''Corynebacterium'' sp.).<ref name=":2" />

The antibacterial activity of IONPs is primarily attributed to the generation of reactive oxygen species (ROS), a mechanism similar to the Fenton reaction.<ref name=":2" /> Specifically, Fe²⁺ ions react with hydrogen peroxide (H₂O₂), producing Fe³⁺ ions and hydroxyl radicals.<ref>{{Cite journal |last1=Groiss |first1=Silvia |last2=Selvaraj |first2=Raja |last3=Varadavenkatesan |first3=Thivaharan |last4=Vinayagam |first4=Ramesh |date=2017-01-15 |title=Structural characterization, antibacterial and catalytic effect of iron oxide nanoparticles synthesised using the leaf extract of Cynometra ramiflora |url=https://www.sciencedirect.com/science/article/abs/pii/S0022286016309589 |journal=Journal of Molecular Structure |volume=1128 |pages=572–578 |doi=10.1016/j.molstruc.2016.09.031 |bibcode=2017JMoSt1128..572G |issn=0022-2860|url-access=subscription }}</ref> These highly reactive species induce oxidative damage to bacterial DNA, ultimately leading to cell death.

==See also== *Health and safety hazards of nanomaterials *Environmental implications of nanotechnology

==References== {{Reflist}}

==External links== * [http://www.nano.gov National Nanotechnology Initiative] * [http://www.understandingnano.com/water.html Nanotechnology methods to clean up water pollution] * [https://web.archive.org/web/20131029020046/http://nanoiron.cz/en/applications Largescale production and applications of zero-valent iron nanoparticles (nZVI)]

Category:Nanoparticles by composition Category:Environmental science Category:Pollution control technologies Category:Iron