Nanoparticles Designed for Dual-Mode Imaging

Dec 18, 2006

Nanoscale, inorganic fluorescent imaging agents such as quantum dots have become an important tool for researchers studying key biomolecules involved in cancer. At the same time, magnetic iron oxide nanoparticles are proving to be useful in detecting tumors and metastatic lesions thanks to their ability to act as powerful contrast agents for use with magnetic resonance imaging (MRI).

Now, researchers at Korea’s Yonsei University, have married the best characteristics of these two types of nanoparticles to create a single nanoparticle probe that can yield clinically useful images of both tumors and the molecules involved in cancer.

Writing in the journal Angewandte Chemie International Edition, Jinwoo Cheon, Ph.D., and his colleagues describe the construction of their biocompatible dual-mode nanoparticle. The investigators start by synthesizing 30-nanometer-diameter silica nanoparticles impregnated with rhodamine, a bright fluorescent dye, and 9-nanometer-diameter water-soluble iron oxide nanoparticles. They then mix these two nanoparticles with a chemical linker, yielding the dual-mode nanoparticle. On average, ten magnetic iron oxide particles link to a single dye-containing silica nanoparticle, and the resulting construct is approximately 45 nanometers in diameter.

In somewhat of a surprise, the combination nanoparticle performed better in both MRI and fluorescent imaging tests than did the individual components. In MRI experiments, the combination nanoparticle generated an MRI signal that was over three-fold more intense than did the same number of iron oxide nanoparticles. Similarly, the fluorescent signal from the dual-mode nanoparticle was almost twice as bright as that produced by dye molecules linked directly to iron oxide nanoparticles.

Next, the researchers labeled the dual-mode nanoparticles with an antibody that binds to molecules known as polysialic acids, which are found on the surface of certain nerve cell and lung tumors. These targeted nanoparticles were quickly taken up by cultured tumor cells and were readily visible using fluorescence microscopy.

This work, which was supported by the National Cancer Institute Alliance for Nanotechnology Excellence, is detailed in a paper titled, “Dual-mode nanoparticle probes for high-performance magnetic resonance and fluorescence imaging of neuroblastoma.” This paper is available at the researcher’s website.

A second paper, in which the researchers detail their development of a second dual-mode nanoparticle, was published in the Journal of the American Chemical Society. This paper, titled, “Biocompatible heterostructured nanoparticles for multimodal biological detection,” is also available at the researcher’s website.

Source: National Cancer Institute

Explore further: Optically activating a cell signaling pathway using carbon nanotubes

add to favorites email to friend print save as pdf

Related Stories

Amazon says FAA drone approval already obsolete

2 hours ago

The approval federal aviation officials gave Amazon.com last week to test a specific drone design outdoors is already outdated, the company's top policy executive said Tuesday in written testimony to a Senate subcommittee.

Firm combines 3-D printing with ancient foundry method

2 hours ago

A century-old firm that's done custom metal work for some of the nation's most prestigious buildings has combined 3-D printing and an ancient foundry process for a project at the National Archives Building in Washington, ...

Recommended for you

Designer's toolkit for dynamic DNA nanomachines

Mar 26, 2015

The latest DNA nanodevices created at the Technische Universitaet Muenchen (TUM)—including a robot with movable arms, a book that opens and closes, a switchable gear, and an actuator—may be intriguing ...

Simple method of binding pollutants in water

Mar 26, 2015

New types of membrane adsorbers remove unwanted particles from water and also, at the same time, dissolved substances such as the hormonally active bis-phenol A or toxic lead. To do this, researchers at the ...

Gold nanoparticles for targeted cancer treatment

Mar 26, 2015

The use of tiny drug-loaded nanocarriers for the safe, targeted delivery of drugs to designated parts of the body has received much press in recent years. Human trials of nanocarriers targeting pancreatic ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.