Nanoparticle Technology to Change Medical Diagnostics

Experts in the field of nanoparticle technology believe a new diagnostic technique based on tagged DNA molecules may revolutionize medical diagnostics.

In a paper published in the April 27, 2004, online edition of the Journal of the American Chemical Society, researchers gave details on the fabrication and use of microscopic "bio-barcodes,” disease-specific DNA segments tagged with magnetic and gold markers.

The bio-barcodes are the result of research carried out at Northwestern University (Evanston, IL, USA). At the core of the technique are two sets of nanoparticle probes 15 nanometers in size. One probe includes a magnetic nanoparticle containing a single DNA strand that matches the target DNA. The other probe consists of a gold nanoparticle attached to a DNA strand that also matches the target DNA. If a genetic sequence of interest is present, its DNA marker becomes sandwiched between the two probes, is separated magnetically, scanned, and identified.

Bio-barcodes were detected with the Verigene instrument manufactured by Nanosphere, Inc. (Northbrook, IL, USA). This optical detection instrument has the ability to identify biologic targets at low concentrations. The manufacturers state that the instrument and its components enable less-skilled lab personnel to produce automatic, definitive results. No target amplification such as is required for polymerase chain reaction (PCR) or real-time PCR is required. Nanosphere, Inc. is currently developing a handheld version of the instrument that is designed to allow bio-bar-code tests to be used at point-of-care settings such as doctor's offices, hospital bedsides, and even patients' homes.

So far, biobar codes have been applied successfully to the detection of anthrax lethal factor and prostate specific antigen. Senior author Professor Chad Merkin, director of the Institute for Nanotechnology at Northwestern University and co-founder of Nanosphere, Inc., predicted, "One could conceivably develop a bar-code for every disease-related protein or DNA sequence.”




Related Links:
Northwestern University
Nanosphere, Inc.