Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Diagnostic method based on nanoscience could rival PCR

28.04.2004


Since the advent of the polymerase chain reaction (PCR) nearly 20 years ago, scientists have been trying to overturn this method for analyzing DNA with something better. The "holy grail" in this quest is a simple method that could be used for point-of-care medical diagnostics, such as in the doctor’s office or on the battlefield.

Now chemists at Northwestern University have set a DNA detection sensitivity record for a diagnostic method that is not based on PCR -- giving PCR a legitimate rival for the first time. Their results were published online today (April 27) by the Journal of the American Chemical Society (JACS).

"We are the first to demonstrate technology that can compete with -- and beat -- PCR in many of the relevant categories," said Chad A. Mirkin, director of Northwestern’s Institute for Nanotechnology, who led the research team. "Nanoscience has made this possible. Our alternative method promises to bring diagnostics to places PCR is unlikely to go -- the battlefield, the post office, a Third World village, the hospital and, perhaps ultimately, the home."



The new selective and ultra-sensitive technology, which is based on gold nanoparticles and DNA, is easier to use, considerably faster, more accurate and less expensive than PCR, making it a leading candidate for use in point-of-care diagnostics. The method, called bio-bar-code amplification (BCA), can test a small sample and quickly deliver an accurate result. BCA also can scan a sample for many different disease targets simultaneously.

The Northwestern team has demonstrated that the BCA method can detect as few as 10 DNA molecules in an entire sample in a matter of minutes, making it as sensitive as PCR. The technology is highly selective, capable of differentiating single-base mismatches and thereby reducing false positives.

In their experiments, the scientists used the anthrax lethal factor, which is important for bioterrorism and has been well studied in the literature, as their target DNA.

The BCA approach builds on earlier work reported last September in the journal Science where Mirkin and colleagues used BCA to detect proteins, specifically prostate specific antigen, at low levels.

For the DNA detection, the team used commercially available materials to outfit a magnetic microparticle and a gold nanoparticle each with a different oligonucleotide, a single strand of DNA that is complementary to the target DNA. When in solution, the oligonucleotides "recognize" and bind to the DNA, sandwiching the DNA between the two particles.

Attached to each tiny gold nanoparticle (just 30 nanometers in diameter) are hundreds to thousands of identical strands of DNA. Mirkin calls this "bar-code DNA" because they have designed it as a unique label specific to the DNA target. After the "particle-DNA-particle" sandwich is removed magnetically from solution, the bar-code DNA is removed from the sandwich and read using standard DNA detection methodologies.

"For each molecule of captured target DNA, thousands of bar-code DNA strands are released, which is a powerful way of amplifying the signal for a DNA target of interest, such as anthrax," said Mirkin, also George B. Rathmann Professor of Chemistry. "There is power in its simplicity."

The technology could be commercially available for certain diseases in one year, Mirkin said.

In addition to Mirkin, other authors on the JACS paper are Jwa-Min Nam and Savka I. Stoeva, from Northwestern University. The research was supported by the Air Force Office of Scientific Research, the Defense Advanced Research Projects Agency, the National Science Foundation and the National Institutes of Health.

Megan Fellman | EurekAlert!
Further information:
http://www.northwestern.edu/

More articles from Life Sciences:

nachricht Monitoring biodiversity with sound: how machines can enrich our knowledge
18.06.2019 | Georg-August-Universität Göttingen

nachricht Uncovering hidden protein structures
18.06.2019 | Universität Konstanz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Uncovering hidden protein structures

18.06.2019 | Life Sciences

Monitoring biodiversity with sound: how machines can enrich our knowledge

18.06.2019 | Life Sciences

Schizophrenia: Adolescence is the game-changer

18.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>