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Nanoshell

January 01, 1970

A nanoshell, or rather a nanoshell plasmon, is a type of spherical nanoparticle consisting of a dielectric core which is covered by a thin metallic shell (usually gold).[1] These nanoshells involve a quasiparticle called a plasmon which is a collective excitation or quantum plasma oscillation where the electrons simultaneously oscillate with respect to all the ions.

Figure 1. s-polarization and p-polarization

The simultaneous oscillation can be called plasmon hybridization where the tunability of the oscillation is associated with mixture of the inner and outer shell where they hybridize to give a lower energy or higher energy. This lower energy couples strongly to incident light, whereas the higher energy is an anti-bonding and weakly combines to incident light. The hybridization interaction is stronger for thinner shell layers, hence, the thickness of the shell and overall particle radius determines which wavelength of light it couples with.[2] Nanoshells can be varied across a broad range of the light spectrum that spans the visible and near infrared regions. The interaction of light and nanoparticles affects the placement of charges which affects the coupling strength. Incident light polarized parallel to the substrate gives a s-polarization (Figure 1b), hence the charges are further from the substrate surface which gives a stronger interaction between the shell and core. Otherwise, a p-polarization is formed which gives a more strongly shifted plasmon energy causing a weaker interaction and coupling.

Discovery edit

The discovery of the nanoshell was made by Professor Naomi J. Halas and her team at Rice University in 2003. When she and her team discovered nanoshells, they weren't initially sure what potential such nanoshells held. "We said, 'Gee, what could it be good for?'" Halas told CNN. After many suggestions, cancer therapy came out of ongoing collaborations with bioengineers looking for different types of biomedical applications.[3] "One of our visions", Halas stated, "no less than single visit diagnosis and treatment of cancer".[4] In 2003 Halas was awarded for Best Discovery of 2003 by Nanotechnology Now.[4]

Production edit

A state of the art method for synthesizing gold nanoshells is the use of the Microfluidic Composite Foams. This method has the potential to replace the standard lithographic method of synthesizing plasmonic nanoshells. The production process described below was an experiment performed by Suhanya Duraiswamy and Saif A. Khan of the Department of Chemical and Biomolecular Engineering in Singapore. Although this method was an experiment, it represents the future of nanoshells synthesis.

The materials required for the production of the nanoshells are the following; Tetraethyl orthosilicate, ammonium hydroxide, hydroxylamine hydrochloride, 3-aminopropyl tris, hydrogentetrachloroaurate(III) trihydrate, tetrakis(hydroxymethyl) phosphonium chloride, sodium hydroxide, potassium carbonate, ethanol, Ultrapure water and glassware washed in aqua regia and rinsed thoroughly in water.[5])

The first step in synthesizing nanoshells in this method is by creating the device for the reaction to take place within. Microfluidic device patterns were fabricated onto silicon wafers by standard photolithography using negative photoresist SU-8 2050. Devices were subsequently molded in poly(dimethyl siloxane) (PDMS) using the soft lithography technique.(40) Briefly, PDMS was molded onto the SU-8 masters at 70 °C for 4 h, peeled, cut, and cleaned. Inlet and outlet holes (1/16-in. o.d.) were punched into the device. The microchannels were irreversibly bonded to a glass slide precoated with a thin layer of PDMS after a brief 35 s air plasma treatment. The microchannels have rectangular cross-section and are 300 μm wide, 155 μm deep, and 0.45 m long.[5]

The actual production of the nanoparticles involves pumping "silicone oil, a mixture of gold-seeded silica particles and gold-plating solution and reducing agent solution to the microfluidic device while nitrogen gas was delivered from a cylinder."[5] The plating solution was then left to age, in a controlled environment, for longer than 24 hours. After the aging process, the fluid is collected from the Microfluidic Device and placed in a centrifuge. The resulting liquid has a layer of oil on the surface with a solution below that contains the nanoshells.

The reason this method is revolutionary is that the size and relative thickness of the gold nanoshell can be controlled by changing the amount of time the reaction is allowed to take place as well as the concentration of the plating solution. Thereby allowing researchers to tailor the particles to suit their given needs. Albeit for optics or cancer treatment.

Cancer treatment edit

Gold-shelled nanoparticles, which are spherical nanoparticles with silica and/or liposome cores[6] and gold shells, are used in cancer therapy and bio-imaging enhancement. Theranostic probes – capable of detection and treatment of cancer in a single treatment – are nanoparticles that have binding sites on their shell that allow them to attach to a desired location (typically cancerous cells) then can be imaged through dual modality imagery (an imaging strategy that uses x-rays and radionuclide imaging) and through near-infrared fluorescence.[7] The reason gold nanoparticles are used is due to their vivid optical properties which are controlled by their size, geometry, and their surface plasmons. Gold nanoparticles (such as AuNPs) have the benefit of being biocompatible and the flexibility to have multiple different molecules, and fundamental materials, attached to their shell (almost anything that can normally be attached to gold can be attached to the gold nano-shell, which can be used in helping identifying and treating cancer). The treatment of cancer is possible only because of the scattering and absorption that occurs for plasmonics. Under scattering, the gold-plated nano-particles become visible to imaging processes that are tuned to the correct wavelength which is dependent upon the size and geometry of the particles. Under absorption, photothermal ablation occurs, which heats the nanoparticles and their immediate surroundings to temperatures capable of killing the cancer cells. This is accomplished with minimal damage to cells in the body due to the utilization of the "water window" (the spectral range between 800 and 1300 nm).[1] As the human body is mostly water, this optimizes the light used versus the effects rendered.

These gold nanoshells are shuttled into tumors by the use of phagocytosis, where phagocytes engulf the nanoshells through the cell membrane to form an internal phagosome, or macrophage. After this it is shuttled into a cell and enzymes are usually used to metabolize it and shuttle it back out of the cell. These nanoshells are not metabolized so for them to be effective they just need to be within the tumor cells and photo-induced cell death (as described above) is used to terminate the tumor cells. This scheme is shown in Figure 2.

 
Figure 2. Nanoshells taken into tumors.

Nanoparticle-based therapeutics have been successfully delivered into tumors by exploiting the enhanced permeability and retention effect, a property that permits nanoscale structures to be taken up passively into tumors without the assistance of antibodies.[4] Delivery of nanoshells into the important regions of tumors can be very difficult. This is where most nanoshells try to exploit the tumor's natural recruitment of monocytes for delivery as seen in the above figure. This delivery system is called a "Trojan Horse".[8]

This process works so well since tumors are about ¾ macrophages and once monocytes are brought into the tumor, it differentiates into macrophages which would also be need to maintain the cargo nanoparticles. Once the nanoshells are at the necrotic center, near-infrared illumination is used to destroy the tumor associated macrophages.

Additionally, these nanoparticles can be made to release antisense DNA oligonucleotides when under photo-activation. These oligonucleotides are used in conjunction with the photo-thermal ablation treatments to perform gene-therapy. This is accomplished because nanoparticle complexes are delivered inside of cells then undergo light induced release of DNA from their surface. This will allow for the internal manipulation of a cell and provide a means for monitoring a group cells return to equilibrium.[9]

Another example of nanoshell plasmonics in cancer treatment involves placing drugs inside of the nanoparticle and using it as a vehicle to deliver toxic drugs to cancerous sites only.[10] This is accomplished by coating the outside of a nanoparticle with iron oxide (allowing for easy tracking with an MRI machine), then once the area of the tumor is coated with the drug-filled nanoparticles, the nanoparticles can be activated using resonant light waves to release the drug.

See also edit

References edit

  1. ^ a b Loo, C; Lin, A; Hirsch, L; Lee, Mh; Barton, J; Halas, N; West, J; Drezek, R (February 2004). . Technology in Cancer Research & Treatment. 3 (1): 33–40. doi:10.1177/153303460400300104. PMID 14750891. S2CID 17523671. Archived from the original (Free full text) on 23 October 2007. Retrieved 6 August 2009.
  2. ^ Brinson, Be; Lassiter, Jb; Levin, Cs; Bardhan, R; Mirin, N; Halas, Nj (November 2008). "Nanoshells Made Easy: Improving Au Layer Growth on Nanoparticle Surfaces". Langmuir. 24 (24): 14166–14171. doi:10.1021/la802049p. PMC 5922771. PMID 19360963.
  3. ^ CNN. "Biography: Naomi Halas." CNN. Cable News Network, 11 Mar. 2008. Web. 7 May 2012. <http://edition.cnn.com/2007/TECH/science/06/11/halas.biog/>.
  4. ^ a b "Best Discoveries." – Best of Nanotechnology. Nanotechnology Now, 29 Mar. 2008. Web. 7 May 2012. <http://www.nanotech-now.com/2003-Awards/Best-Discoveries-2003.htm>.
  5. ^ a b c Duraiswamy, Suhanya; Khan, Saif (23 August 2010). "Plasmonic Nanoshell Synthesis in Microfluidic Composite Foams". Nano Letters. 9. 10 (9): 3757–3763. Bibcode:2010NanoL..10.3757D. doi:10.1021/nl102478q. PMID 20731386.
  6. ^ Abbasi, Akram; Park, Keunhan; Bose, Arijit; Bothun, Geoffrey D. (30 May 2017). "Near-Infrared Responsive Gold–Layersome Nanoshells". Langmuir. 33 (21): 5321–5327. doi:10.1021/acs.langmuir.7b01273. ISSN 0743-7463. PMID 28486807.
  7. ^ Bardhan, R; Grady, Nk; Halas, Nj (September 2008). "Nanoscale Control of Near-Infrared Fluorescence Enhancement Using Au Nanoshells". Nano Micro Small. 4 (10): 1716–1722. doi:10.1002/smll.200800405. PMID 18819167.
  8. ^ Choi, Mr; Stanton-Maxey, Kj; Stanley, Jk; Levin, Cs; Bardhan, R; Akin, D; Badve, S; Sturgis, J; Robinson, Jp; Bashir, R; Halas, Nj; Clare, Se (December 2007). "A cellular Trojan Horse for delivery of therapeutic nanoparticles into tumors". Nano Letters. 7 (12): 3759–65. Bibcode:2007NanoL...7.3759C. doi:10.1021/nl072209h. PMID 17979310.
  9. ^ Bardan, R; Lal, S; Joshi, A; Halas, Nj (May 2011). "Theranostic Nanoshells: From Probe Design to Imaging and Treatment of Cancer". Accounts of Chemical Research. 44 (10): 936–946. doi:10.1021/ar200023x. PMC 3888233. PMID 21612199.
  10. ^ "Nanoparticles Used To Target Brain Cancer -- ScienceDaily".

External links edit

  • halas.rice.edu

January 01, 1970
nanoshell, nanoshell, rather, nanoshell, plasmon, type, spherical, nanoparticle, consisting, dielectric, core, which, covered, thin, metallic, shell, usually, gold, these, nanoshells, involve, quasiparticle, called, plasmon, which, collective, excitation, quan. A nanoshell or rather a nanoshell plasmon is a type of spherical nanoparticle consisting of a dielectric core which is covered by a thin metallic shell usually gold 1 These nanoshells involve a quasiparticle called a plasmon which is a collective excitation or quantum plasma oscillation where the electrons simultaneously oscillate with respect to all the ions Figure 1 s polarization and p polarization The simultaneous oscillation can be called plasmon hybridization where the tunability of the oscillation is associated with mixture of the inner and outer shell where they hybridize to give a lower energy or higher energy This lower energy couples strongly to incident light whereas the higher energy is an anti bonding and weakly combines to incident light The hybridization interaction is stronger for thinner shell layers hence the thickness of the shell and overall particle radius determines which wavelength of light it couples with 2 Nanoshells can be varied across a broad range of the light spectrum that spans the visible and near infrared regions The interaction of light and nanoparticles affects the placement of charges which affects the coupling strength Incident light polarized parallel to the substrate gives a s polarization Figure 1b hence the charges are further from the substrate surface which gives a stronger interaction between the shell and core Otherwise a p polarization is formed which gives a more strongly shifted plasmon energy causing a weaker interaction and coupling Contents 1 Discovery 2 Production 3 Cancer treatment 4 See also 5 References 6 External linksDiscovery editThe discovery of the nanoshell was made by Professor Naomi J Halas and her team at Rice University in 2003 When she and her team discovered nanoshells they weren t initially sure what potential such nanoshells held We said Gee what could it be good for Halas told CNN After many suggestions cancer therapy came out of ongoing collaborations with bioengineers looking for different types of biomedical applications 3 One of our visions Halas stated no less than single visit diagnosis and treatment of cancer 4 In 2003 Halas was awarded for Best Discovery of 2003 by Nanotechnology Now 4 Production editA state of the art method for synthesizing gold nanoshells is the use of the Microfluidic Composite Foams This method has the potential to replace the standard lithographic method of synthesizing plasmonic nanoshells The production process described below was an experiment performed by Suhanya Duraiswamy and Saif A Khan of the Department of Chemical and Biomolecular Engineering in Singapore Although this method was an experiment it represents the future of nanoshells synthesis The materials required for the production of the nanoshells are the following Tetraethyl orthosilicate ammonium hydroxide hydroxylamine hydrochloride 3 aminopropyl tris hydrogentetrachloroaurate III trihydrate tetrakis hydroxymethyl phosphonium chloride sodium hydroxide potassium carbonate ethanol Ultrapure water and glassware washed in aqua regia and rinsed thoroughly in water 5 The first step in synthesizing nanoshells in this method is by creating the device for the reaction to take place within Microfluidic device patterns were fabricated onto silicon wafers by standard photolithography using negative photoresist SU 8 2050 Devices were subsequently molded in poly dimethyl siloxane PDMS using the soft lithography technique 40 Briefly PDMS was molded onto the SU 8 masters at 70 C for 4 h peeled cut and cleaned Inlet and outlet holes 1 16 in o d were punched into the device The microchannels were irreversibly bonded to a glass slide precoated with a thin layer of PDMS after a brief 35 s air plasma treatment The microchannels have rectangular cross section and are 300 mm wide 155 mm deep and 0 45 m long 5 The actual production of the nanoparticles involves pumping silicone oil a mixture of gold seeded silica particles and gold plating solution and reducing agent solution to the microfluidic device while nitrogen gas was delivered from a cylinder 5 The plating solution was then left to age in a controlled environment for longer than 24 hours After the aging process the fluid is collected from the Microfluidic Device and placed in a centrifuge The resulting liquid has a layer of oil on the surface with a solution below that contains the nanoshells The reason this method is revolutionary is that the size and relative thickness of the gold nanoshell can be controlled by changing the amount of time the reaction is allowed to take place as well as the concentration of the plating solution Thereby allowing researchers to tailor the particles to suit their given needs Albeit for optics or cancer treatment Cancer treatment editGold shelled nanoparticles which are spherical nanoparticles with silica and or liposome cores 6 and gold shells are used in cancer therapy and bio imaging enhancement Theranostic probes capable of detection and treatment of cancer in a single treatment are nanoparticles that have binding sites on their shell that allow them to attach to a desired location typically cancerous cells then can be imaged through dual modality imagery an imaging strategy that uses x rays and radionuclide imaging and through near infrared fluorescence 7 The reason gold nanoparticles are used is due to their vivid optical properties which are controlled by their size geometry and their surface plasmons Gold nanoparticles such as AuNPs have the benefit of being biocompatible and the flexibility to have multiple different molecules and fundamental materials attached to their shell almost anything that can normally be attached to gold can be attached to the gold nano shell which can be used in helping identifying and treating cancer The treatment of cancer is possible only because of the scattering and absorption that occurs for plasmonics Under scattering the gold plated nano particles become visible to imaging processes that are tuned to the correct wavelength which is dependent upon the size and geometry of the particles Under absorption photothermal ablation occurs which heats the nanoparticles and their immediate surroundings to temperatures capable of killing the cancer cells This is accomplished with minimal damage to cells in the body due to the utilization of the water window the spectral range between 800 and 1300 nm 1 As the human body is mostly water this optimizes the light used versus the effects rendered These gold nanoshells are shuttled into tumors by the use of phagocytosis where phagocytes engulf the nanoshells through the cell membrane to form an internal phagosome or macrophage After this it is shuttled into a cell and enzymes are usually used to metabolize it and shuttle it back out of the cell These nanoshells are not metabolized so for them to be effective they just need to be within the tumor cells and photo induced cell death as described above is used to terminate the tumor cells This scheme is shown in Figure 2 nbsp Figure 2 Nanoshells taken into tumors Nanoparticle based therapeutics have been successfully delivered into tumors by exploiting the enhanced permeability and retention effect a property that permits nanoscale structures to be taken up passively into tumors without the assistance of antibodies 4 Delivery of nanoshells into the important regions of tumors can be very difficult This is where most nanoshells try to exploit the tumor s natural recruitment of monocytes for delivery as seen in the above figure This delivery system is called a Trojan Horse 8 This process works so well since tumors are about macrophages and once monocytes are brought into the tumor it differentiates into macrophages which would also be need to maintain the cargo nanoparticles Once the nanoshells are at the necrotic center near infrared illumination is used to destroy the tumor associated macrophages Additionally these nanoparticles can be made to release antisense DNA oligonucleotides when under photo activation These oligonucleotides are used in conjunction with the photo thermal ablation treatments to perform gene therapy This is accomplished because nanoparticle complexes are delivered inside of cells then undergo light induced release of DNA from their surface This will allow for the internal manipulation of a cell and provide a means for monitoring a group cells return to equilibrium 9 Another example of nanoshell plasmonics in cancer treatment involves placing drugs inside of the nanoparticle and using it as a vehicle to deliver toxic drugs to cancerous sites only 10 This is accomplished by coating the outside of a nanoparticle with iron oxide allowing for easy tracking with an MRI machine then once the area of the tumor is coated with the drug filled nanoparticles the nanoparticles can be activated using resonant light waves to release the drug See also edit nbsp Science portal nbsp Technology portalReferences edit a b Loo C Lin A Hirsch L Lee Mh Barton J Halas N West J Drezek R February 2004 Nanoshell enabled photonics based imaging and therapy of cancer Technology in Cancer Research amp Treatment 3 1 33 40 doi 10 1177 153303460400300104 PMID 14750891 S2CID 17523671 Archived from the original Free full text on 23 October 2007 Retrieved 6 August 2009 Brinson Be Lassiter Jb Levin Cs Bardhan R Mirin N Halas Nj November 2008 Nanoshells Made Easy Improving Au Layer Growth on Nanoparticle Surfaces Langmuir 24 24 14166 14171 doi 10 1021 la802049p PMC 5922771 PMID 19360963 CNN Biography Naomi Halas CNN Cable News Network 11 Mar 2008 Web 7 May 2012 lt http edition cnn com 2007 TECH science 06 11 halas biog gt a b Best Discoveries Best of Nanotechnology Nanotechnology Now 29 Mar 2008 Web 7 May 2012 lt http www nanotech now com 2003 Awards Best Discoveries 2003 htm gt a b c Duraiswamy Suhanya Khan Saif 23 August 2010 Plasmonic Nanoshell Synthesis in Microfluidic Composite Foams Nano Letters 9 10 9 3757 3763 Bibcode 2010NanoL 10 3757D doi 10 1021 nl102478q PMID 20731386 Abbasi Akram Park Keunhan Bose Arijit Bothun Geoffrey D 30 May 2017 Near Infrared Responsive Gold Layersome Nanoshells Langmuir 33 21 5321 5327 doi 10 1021 acs langmuir 7b01273 ISSN 0743 7463 PMID 28486807 Bardhan R Grady Nk Halas Nj September 2008 Nanoscale Control of Near Infrared Fluorescence Enhancement Using Au Nanoshells Nano Micro Small 4 10 1716 1722 doi 10 1002 smll 200800405 PMID 18819167 Choi Mr Stanton Maxey Kj Stanley Jk Levin Cs Bardhan R Akin D Badve S Sturgis J Robinson Jp Bashir R Halas Nj Clare Se December 2007 A cellular Trojan Horse for delivery of therapeutic nanoparticles into tumors Nano Letters 7 12 3759 65 Bibcode 2007NanoL 7 3759C doi 10 1021 nl072209h PMID 17979310 Bardan R Lal S Joshi A Halas Nj May 2011 Theranostic Nanoshells From Probe Design to Imaging and Treatment of Cancer Accounts of Chemical Research 44 10 936 946 doi 10 1021 ar200023x PMC 3888233 PMID 21612199 Nanoparticles Used To Target Brain Cancer ScienceDaily External links edithalas rice edu Retrieved from https en wikipedia org w index php title Nanoshell amp oldid 1184110209, wikipedia, wiki, book, books, library,

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