One of the challenges with current cancer treatments is how to deliver drugs to tumors without causing debilitating side effects. By delivering drugs in a more targeted way, some of those side effects can be reduced. There are several companies and universities developing targeted drug delivery using nanoparticles. One method being developed by researchers at MIT and University of California at San Diego and Santa Barbara looks interesting. They have divided the task between two nanoparticles in order to increase the targeting effectiveness.

The approach involves several steps. First, they inject gold nanorods into the blood stream. The gold nanorods stay in the healthy blood vessels but exit the leaky blood vessels found at the site of tumors. The gold nanorods then accumulate in the tumor and an infrared laser is used to heat the gold nanorods, thereby heating the tumor.

The heating of a tumor increases the level of a stress related protein (called p32) on the surface of the tumor. Because an amino acid (called LyP-1) binds to the p32 protein,they developed a process to attach LyP-1 to spherical nanoparticles called liposomes. They then insert molecules of a chemotherapy drug inside the liposome.

When the drug packed liposome is injected into the bloodstream the amino acids on the nanoparticles attach to the proteins the heat has pushed to the surface of the tumor and more of the drug is delivered to the tumor.

Why Nanorods Work Better Than Nanospheres

Several methods in use today use spherical gold nanoparticles for drug delivery, so why did this group choose nanorods instead? It turns out that nanorods of different lengths absorb different frequencies of infrared radiation. The company making the nanorods, NanopartzTM, has shown that gold nanorods absorb infrared much more efficiently than spherical gold nanoparticles. Therefore gold nanorods do a better job of absorbing infrared light and heating up the tumor than spherical nanoparticles do.

It’s interesting to see this concept of using a combination of different nanoparticles doing different parts of the task to develop a system to deliver chemotherapy drugs to cancer tumors. It will be very interesting to see which of the several methods of targeted drug delivery under development is put into widespread use.

For clear explanations of other ways nanotechnology is being used to improve the effectiveness and safety of cancer treatment go to my Cancer Treatment Web page at http://www.understandingnano.com/cancer-treatment-nanotechnology.html

For clear explanations of how nanoparticles are being used in various fields go to my Applications of Nanoparticles Web page at http://www.understandingnano.com/nanoparticles.html

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Comment by Fujun Liu on January 27, 2010 at 9:59pm
That seems interesting! I just wonder if the spherical gold np with different radius will do that, as well as nanorods do?

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Welcome! Nanopaprika was cooked up by Hungarian chemistry PhD student in 2007. The main idea was to create something more personal than the other nano networks already on the Internet. Community is open to everyone from post-doctorial researchers and professors to students everywhere.

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Publications by A. Paszternák:

Pd/Ni Synergestic Activity for Hydrogen Oxidation Reaction in Alkaline Conditions

The potential use of cellophane test strips for the quick determination of food colours

pH and CO2 Sensing by Curcumin-Coloured Cellophane Test Strip

Polymeric Honeycombs Decorated by Nickel Nanoparticles

Directed Deposition of Nickel Nanoparticles Using Self-Assembled Organic Template,

Organometallic deposition of ultrasmooth nanoscale Ni film,

Zigzag-shaped nickel nanowires via organometallic template-free route

Surface analytical characterization of passive iron surface modified by alkyl-phosphonic acid layers

Atomic Force Microscopy Studies of Alkyl-Phosphonate SAMs on Mica

Amorphous iron formation due to low energy heavy ion implantation in evaporated 57Fe thin films

Surface modification of passive iron by alkylphosphonic acid layers

Formation and structure of alkylphosphonic acid layers on passive iron

Structure of the nonionic surfactant triethoxy monooctylether C8E3 adsorbed at the free water surface, as seen from surface tension measurements and Monte Carlo simulations