Home > Press > Good as Gold
Gold nanoparticles improve sensitivity and specificity of genetic analysis and diagnosis
Good as Gold
June 27, 2005
Even though they don't shine, they're still worth their
weight in gold: nanoscopic particles made of gold are used
for a number of technical and scientific purposes. Now
these tiny golden particles are being put to use in another
area. Chinese scientists have discovered that the
polymerase chain reaction (PCR), the basis for modern
genetic testing methods, works markedly better in the
presence of gold nanoparticles.
As we all know from murder mysteries, a few flakes of skin
under the victim's fingernails or saliva residue on an
envelope's adhesive strip are enough to reveal the
perpetrator. The tiny amount of genetic material in these
samples is enough to give a genetic fingerprint that can be
compared with known samples and assigned unambiguously to a
single person. PCR takes all the credit for this; this
tremendously efficient technique allows the complete
genotype or a select region of the genome to be copied.
Within a few hours, there is enough material for a variety
of biological and medical tests. PCR is indispensable not
only for forensics but also in research and diagnosis, for
the identification and quantification of pathogens.
Here's how PCR works: the genetic material is in the form
of double strands of DNA, which are first separated into
single strands. A segment of the DNA sequence to be
examined is marked with a short synthetic piece of single-
stranded DNA, the primer. Starting at the primer, an enzyme
then gets to work copying the strand, building block by
building block. This procedure, splitting the DNA into
single strands and copying it, is repeated again and again.
Each cycle doubles the amount of DNA. Errors do occur in
this process, which are then passed on in the copies,
compromising sensitivity and specificity. This is where
Chunhai Fan, Jun Hu, Zhizhou Zhang and their team step in.
Their nanogold binds substantially more tightly to single-
stranded than to double-stranded DNA. This effect seems to
be responsible for the fact that in the presence of gold
particles, fewer errors occur in the PCR and the yield is
improved. This makes it possible to use smaller DNA samples
from the start.
The effect of the nanogold particles is not completely
understood. It is clearly analogous to a natural error
avoidance system: in cells, the protein SSB binds to
single-stranded DNA, but not to double-stranded DNA,
hindering mismatches between the strand to be copied and
the natural primer.
About John Wiley & Sons, Inc.:
Founded in 1807, John Wiley & Sons, Inc., provides must-
have content and services to customers worldwide. Our core
businesses include scientific, technical, and medical
journals, encyclopedias, books, and online products and
services; professional and consumer books and subscription
services; and educational materials for undergraduate and
graduate students and lifelong learners. Wiley has
publishing, marketing, and distribution centers in the
United States, Canada, Europe, Asia, and Australia. The
company is listed on the New York Stock Exchange under the
symbols JWa and JWb.
For more information, please visit www.wiley.com
Copyright © John Wiley & Sons
If you have a comment, please Contact
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Angewandte Chemie International Ed.
Nanoliposomes Help Efforts to Cure Bacterial Infections January 27th, 2015
Stomach acid-powered micromotors get their first test in a living animal January 27th, 2015
Engineering self-assembling amyloid fibers January 26th, 2015
Promising use of nanodiamonds in delivering cancer drug to kill cancer stem cells: NUS study shows that delivery of Epirubicin by nanodiamonds resulted in a normally lethal dosage of Epirubicin becoming a safe and effective dosage for treatment of liver cancer January 26th, 2015
Industrial Nanotech, Inc. Announces New OEM Customer January 27th, 2015
Carbon nanoballs can greatly contribute to sustainable energy supply January 27th, 2015
The laser pulse that gets shorter all by itself: Ultrashort laser pulses have become an indispensable tool for atomic and molecular research; A new technology makes creating short infrared pulses easy and cheap January 27th, 2015
New pathway to valleytronics January 27th, 2015