Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Making Cancer Cells Visible

Abstract:
Tumor proteases change the magnetic properties of nanoparticles

Making Cancer Cells Visible

Posted on May 08, 2006

Wouldn’t it be nice if we could detect tumors and their metastases as easily as we find broken bones with X-rays? A team of scientists headed by S. Bhatia in Boston (USA) has been working on this problem. They have found a way to make a tumor-specific protease visible by using Fe3O4 nanoparticles and magnetic resonance imaging (MRI).

Organic tissue is mostly made of water and fat, substances that contain many protons (positively charged hydrogen ions or hydrogen nuclei). These have an intrinsic angular momentum, known as spin, and thus a magnetic moment. In a magnetic field, they line up and rotate with a certain frequency that is proportional to the strength of the external field. If electromagnetic waves with the same frequency (resonance) are beamed in, they disturb the orientation of the protons in the external material field. When the electromagnetic wave is switched off, the protons flip back to their original position, which causes them to give off an electromagnetic signal of their own. This can be detected and gives information about the proton density and the chemical environment in the region being studied. These data allow for the computation of a 3D image that depicts the different tissues in the body.

How can this be used to detect mutated cells with the best possible resolution and high confidence? The Boston researchers used nanoparticles of Fe3O4 whose magnetic properties change when they aggregate into large multimeric complexes.

Two biomolecules that bind to each other with high affinity, biotin and neutravidin, act as a “glue” to hold the Fe3O4 particles together. Half of the nanoparticles are coated with biotin, the other half with neutravidin. Long polyethylene glycol (PEG) chains are coupled to these biomolecules in order to keep the particles from interacting with each other. The anchor for the PEG chains is a peptide that contains a segment that can be cleaved by a tumor-specific enzyme, matrix metalloproteinase-2 (MMP-2).

MMP-2 is mostly found in the immediate area around growing tumor cells, meaning that the PEG chains are only cleaved from the Fe3O4nanoparticles when they are near a tumor. This then allows the biotin–neutrovidin glue to do its job—the Fe3O4 particles aggregate and the tumor becomes visible in the MRI image.

####


Author: Sangeeta N. Bhatia, Massachusetts Institute of Technology, Cambridge (USA), lmrt.mit.edu/personnel/sangeeta.asp

Title: Proteolytic Actuation of Nanoparticle Self-Assembly

Angewandte Chemie International Edition, 2006, 45, No. 19, 3161–3165, doi: 10.1002/anie.200600259

Contact:
Editorial office:
angewandte@wiley-vch.de

or David Greenberg (US)
dgreenbe@wiley.com

or Julia Lampam (UK)
jlampam@wiley.co.uk

Copyright © Angewandte Chemie

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Nanomedicine

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Advances in priming B cell immunity against HIV pave the way to future HIV vaccines, shows quartet of new studies May 17th, 2024

New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024

Materials/Metamaterials/Magnetoresistance

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Focused ion beam technology: A single tool for a wide range of applications January 12th, 2024

Catalytic combo converts CO2 to solid carbon nanofibers: Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material January 12th, 2024

Announcements

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project