Editing Nanoshell (section)

==Cancer treatment==
Gold-shelled nanoparticles, which are spherical nanoparticles with silica and/or liposome cores<ref>{{Cite journal|last1=Abbasi|first1=Akram|last2=Park|first2=Keunhan|last3=Bose|first3=Arijit|last4=Bothun|first4=Geoffrey D.|date=2017-05-30|title=Near-Infrared Responsive Gold–Layersome Nanoshells|journal=Langmuir|volume=33|issue=21|pages=5321–5327|doi=10.1021/acs.langmuir.7b01273|pmid=28486807|issn=0743-7463}}</ref> and gold shells, are used in cancer therapy and bio-imaging enhancement.
[[Predictive Medicine|Theranostic probes]] – capable of detection and treatment of cancer in a single treatment – are [[nanoparticle]]s that have binding sites on their shell that allow them to attach to a desired location (typically cancerous cells) then can be imaged through [[Preclinical imaging|dual modality imagery]] (an imaging strategy that uses x-rays and [[Nuclear medicine|radionuclide imaging]]) and through near-infrared fluorescence.<ref name=bardhan>{{cite journal|doi = 10.1002/smll.200800405|pmid=18819167|date=Sep 2008|author1=Bardhan, R |author2=Grady, Nk |author3=Halas, Nj |title= Nanoscale Control of Near-Infrared Fluorescence Enhancement Using Au Nanoshells|volume=4|issue=10|pages=1716–1722|journal=Nano Micro Small|author1-link=Rizia Bardhan|author3-link=Naomi Halas|doi-access=free}}</ref> 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 [[Surface plasmon|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 therapy|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&nbsp;nm).<ref name=loo/> 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 [[enzyme]]s 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.

[[File:Attack-cancer.png|right|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 [[monocyte]]s for delivery as seen in the above figure. This delivery system is called a "Trojan Horse".<ref name=choi>{{cite journal|doi=10.1021/nl072209h|date=Dec 2007|author1=Choi, Mr |author2=Stanton-Maxey, Kj |author3=Stanley, Jk |author4=Levin, Cs |author5=Bardhan, R |author6=Akin, D |author7=Badve, S |author8=Sturgis, J |author9=Robinson, Jp |author10=Bashir, R |author11=Halas, Nj |author12=Clare, Se |title=A cellular Trojan Horse for delivery of therapeutic nanoparticles into tumors|volume=7|issue=12|pages=3759–65|pmid=17979310|journal=Nano Letters|bibcode = 2007NanoL...7.3759C }}</ref>

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.<ref>{{cite journal|doi=10.1021/ar200023x|pmid=21612199|date=May 2011|author1=Bardan, R |author2=Lal, S |author3=Joshi, A |author4=Halas, Nj |title=Theranostic Nanoshells: From Probe Design to Imaging and Treatment of Cancer|volume=44|issue=10|pages=936–946|journal=Accounts of Chemical Research|pmc=3888233}}</ref>

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.<ref>{{cite web| url = https://www.sciencedaily.com/releases/2006/11/061115085736.htm| title = Nanoparticles Used To Target Brain Cancer -- ScienceDaily}}</ref> This is accomplished by coating the outside of a nanoparticle with iron oxide (allowing for easy tracking with an [[Magnetic resonance imaging|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.