Colloidal gold

Gold Colloid of varying size
Suspensions of gold nanoparticles of various sizes. The size difference causes the difference in colors.

Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water.^[1] The colloid is coloured usually either wine red (for spherical particles less than 100 nm) or blue-purple (for larger spherical particles or nanorods).^[2] Due to their optical,^[3] electronic, and molecular-recognition properties, gold nanoparticles are the subject of substantial research, with many potential or promised applications in a wide variety of areas, including electron microscopy, electronics,^[4] nanotechnology, materials science,^[5] and biomedicine.^[6]^[7]^[8]^[9]

The properties of colloidal gold nanoparticles, and thus their potential applications, depend strongly upon their size and shape.^[10] For example, rodlike particles have both a transverse and longitudinal absorption peak, and anisotropy of the shape affects their self-assembly.^[11]

^ Voliani, Valerio (2020-04-20). Gold Nanoparticles: An Introduction to Synthesis, Properties and Applications. De Gruyter. doi:10.1515/9781501511455. ISBN 978-1-5015-1145-5. S2CID 219789607.
^ Sapsford KE, Algar WR, Berti L, Gemmill KB, Casey BJ, Oh E, Stewart MH, Medintz IL (March 2013). "Functionalizing nanoparticles with biological molecules: developing chemistries that facilitate nanotechnology". Chemical Reviews. 113 (3): 1904–2074. doi:10.1021/cr300143v. PMID 23432378. S2CID 206896854.
^ Sreekumar, S.; Shah, N.; Mondol, J.; Hewitt, N.; Chakrabarti, S. (February 2022). "Broadband absorbing mono, blended and hybrid nanofluids for direct absorption solar collector: A comprehensive review" (PDF). Nano Futures. 103 (2): 504–515. Bibcode:2022NanoF...6b2002S. doi:10.1088/2399-1984/ac57f7. S2CID 247095942.^{[permanent dead link]}
^ Gorji, Saleh; Cheong, Kuan Yew (2015). "Au nanoparticles embedded at the interface of Al/4H-SiC Schottky contacts for current density enhancement". Applied Physics A. 118 (1): 315–325. Bibcode:2015ApPhA.118..315G. doi:10.1007/s00339-014-8733-4. S2CID 96824985.
^ Torres-Torres, D.; Trejo-Valdez, M.; Castañeda, L.; Torres-Torres, C.; Tamayo-Rivera, L.; Fernández-Hernández, R. C.; Reyes-Esqueda, J. A.; Muñoz-Saldaña, J.; Rangel-Rojo, R.; Oliver, A. (2010-08-02). "Inhibition of the two-photon absorption response exhibited by a bilayer TiO2 film with embedded Au nanoparticles". Optics Express. 18 (16): 16406–16417. Bibcode:2010OExpr..1816406T. doi:10.1364/OE.18.016406. ISSN 1094-4087. PMID 20721027.
^ Yang X, Yang M, Pang B, Vara M, Xia Y (October 2015). "Gold Nanomaterials at Work in Biomedicine". Chemical Reviews. 115 (19): 10410–88. doi:10.1021/acs.chemrev.5b00193. PMID 26293344.
^ Mulvaney P (2003). The beauty and elegance of Nanocrystals: How invisibly small particles will colour and shape our future (Report). University of Melbourne. Archived from the original on 2004-10-28.
^ Rao CN, Kulkarni GU, Thomas PJ, Edwards PP (2000). "Metal nanoparticles and their assemblies". Chemical Society Reviews. 29 (1): 27–35. doi:10.1039/A904518J. S2CID 59025862.
^ Dreaden EC, Alkilany AM, Huang X, Murphy CJ, El-Sayed MA (April 2012). "The golden age: gold nanoparticles for biomedicine". Chemical Society Reviews. 41 (7): 2740–79. doi:10.1039/c1cs15237h. PMC 5876014. PMID 22109657.
^ Zeng S, Yong KT, Roy I, Dinh XQ, Yu X, Luan F (2011). "A review on functionalized gold nanoparticles for biosensing applications" (PDF). Plasmonics. 6 (3): 491–506. doi:10.1007/s11468-011-9228-1. S2CID 34796473. Archived from the original (PDF) on 2017-08-09. Retrieved 2015-09-16.
^ Sharma V, Park K, Srinivasarao M (2009). "Colloidal dispersion of gold nanorods: Historical background, optical properties, seed-mediated synthesis, shape separation and self-assembly". Materials Science and Engineering: R: Reports. 65 (1–3): 1–38. doi:10.1016/j.mser.2009.02.002.

[1] Voliani, Valerio (2020-04-20). Gold Nanoparticles: An Introduction to Synthesis, Properties and Applications. De Gruyter. doi:10.1515/9781501511455. ISBN 978-1-5015-1145-5. S2CID 219789607.

[2] Sapsford KE, Algar WR, Berti L, Gemmill KB, Casey BJ, Oh E, Stewart MH, Medintz IL (March 2013). "Functionalizing nanoparticles with biological molecules: developing chemistries that facilitate nanotechnology". Chemical Reviews. 113 (3): 1904–2074. doi:10.1021/cr300143v. PMID 23432378. S2CID 206896854.

[3] Sreekumar, S.; Shah, N.; Mondol, J.; Hewitt, N.; Chakrabarti, S. (February 2022). "Broadband absorbing mono, blended and hybrid nanofluids for direct absorption solar collector: A comprehensive review" (PDF). Nano Futures. 103 (2): 504–515. Bibcode:2022NanoF...6b2002S. doi:10.1088/2399-1984/ac57f7. S2CID 247095942.^{[permanent dead link]}

[4] Gorji, Saleh; Cheong, Kuan Yew (2015). "Au nanoparticles embedded at the interface of Al/4H-SiC Schottky contacts for current density enhancement". Applied Physics A. 118 (1): 315–325. Bibcode:2015ApPhA.118..315G. doi:10.1007/s00339-014-8733-4. S2CID 96824985.

[5] Torres-Torres, D.; Trejo-Valdez, M.; Castañeda, L.; Torres-Torres, C.; Tamayo-Rivera, L.; Fernández-Hernández, R. C.; Reyes-Esqueda, J. A.; Muñoz-Saldaña, J.; Rangel-Rojo, R.; Oliver, A. (2010-08-02). "Inhibition of the two-photon absorption response exhibited by a bilayer TiO2 film with embedded Au nanoparticles". Optics Express. 18 (16): 16406–16417. Bibcode:2010OExpr..1816406T. doi:10.1364/OE.18.016406. ISSN 1094-4087. PMID 20721027.

[6] Yang X, Yang M, Pang B, Vara M, Xia Y (October 2015). "Gold Nanomaterials at Work in Biomedicine". Chemical Reviews. 115 (19): 10410–88. doi:10.1021/acs.chemrev.5b00193. PMID 26293344.

[ref4-7] Mulvaney P (2003). The beauty and elegance of Nanocrystals: How invisibly small particles will colour and shape our future (Report). University of Melbourne. Archived from the original on 2004-10-28.

[ref5-8] Rao CN, Kulkarni GU, Thomas PJ, Edwards PP (2000). "Metal nanoparticles and their assemblies". Chemical Society Reviews. 29 (1): 27–35. doi:10.1039/A904518J. S2CID 59025862.

[9] Dreaden EC, Alkilany AM, Huang X, Murphy CJ, El-Sayed MA (April 2012). "The golden age: gold nanoparticles for biomedicine". Chemical Society Reviews. 41 (7): 2740–79. doi:10.1039/c1cs15237h. PMC 5876014. PMID 22109657.

[10] Zeng S, Yong KT, Roy I, Dinh XQ, Yu X, Luan F (2011). "A review on functionalized gold nanoparticles for biosensing applications" (PDF). Plasmonics. 6 (3): 491–506. doi:10.1007/s11468-011-9228-1. S2CID 34796473. Archived from the original (PDF) on 2017-08-09. Retrieved 2015-09-16.

[ReferenceA-11] Sharma V, Park K, Srinivasarao M (2009). "Colloidal dispersion of gold nanorods: Historical background, optical properties, seed-mediated synthesis, shape separation and self-assembly". Materials Science and Engineering: R: Reports. 65 (1–3): 1–38. doi:10.1016/j.mser.2009.02.002.

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