A nanoshell is a spherical nanoparticle with a dielectric core covered by a thin metallic shell, usually gold. It was discovered in 2003 by Professor Naomi Halas at Rice University. The nanoshell involves plasmons, which are collective electron oscillations that can be used for cancer therapy applications. Nanoshells are now produced using a microfluidic method involving pumping solutions through microchannels to plate gold onto gold-seeded silica particles, aging the solution, and centrifuging to separate the nanoshells.

1. Nanoshell
P.Samuel, Ph.D
Assistant Professor of Biotechnology,
ANJA College, Sivakasi

2. What is a Nanoshell?
• A Nanoshell, is a type of spherical nanoparticle
consisting of a dielectric core which is covered
by a thin metallic shell (usually gold).
• These Nanoshell 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.

3. Discovery of Nanoshell
• The discovery of the nanoshell was made by
Professor Naomi J. Halas and her team at Rice
University in 2003.
• After many suggestions, cancer therapy came
out of ongoing collaborations with bioengineers
looking for different types of biomedical
applications.
• "One of our visions", Halas stated, "no less than
single visit diagnosis and treatment of cancer".

4. Production of Nanoshell
• Method: Microfluidic Composite Foams, further
this method replace standard lithographic
method.
• The method was explained by Suhanya
Duraiswamy and Saif A. Khan of the Department
of Chemical and Biomolecular Engineering in
Singapore.

5. Materials required for Nanoshell
synthesis
• 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.

6. Steps in production of Nanoshell
Microfluidic device fabricated onto silicon wafers by
standard photolithography using negative photoresist
SU-8 2050
Devices were subsequently molded in poly(dimethyl
siloxane) (PDMS) soft lithography technique.

7. 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.
microchannels were irreversibly bonded to a glass slide
precoated with a thin layer of PDMS
microchannels have rectangular cross-section and are 300 μm
wide, 155 μm deep, and 0.45 m long.
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.

8. • 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.