New detection technology is
always welcome and this one appears able quickly pick up on cancer markers. Obviously this is early days, but with a
working tool, characterizing the markers should advance apace.
It has be come easy to envisage a
future in which a cancer diagnosis is a simple blood test away to be followed
up with a simple treatment consisting of an injection of nanogold combined with
radio heating to eliminate gross problems and a viral attack on any remnants.
It really will and can become
that easy and once all that is in place, humanity will practically forget that
cancer even exists and will hold no fear of it whatsoever. We did the same to small pox and polio.
Tiny particles measure microRNA to detect cancer
18:31 September 2, 2011
Early disease detection can be a matter of life and death, especially
if that disease is cancer. In a novel approach to this problem, researchers
from MIT have engineeringed a series of ultra-microscopic particles, each designed
to bind to a disease-specific type of microRNA - a genetic material which
affects gene expression in the nucleus. In cancer cells, the microRNA has
somehow malfunctioned, leading to rapid, unregulated cell growth that can
ultimately form tumors.
"There are many challenges to detecting microRNA. There's not an
accepted gold standard," says MIT team leader and professor of chemical
engineering Patrick Doyle. "Everybody has their own favorite one."
First discovered in 1993, microRNAs are short pieces of
non-protein-coding regulatory ribonucleic acid (RNA) averaging 20 nucleotides
in length. To date, nearly 1000 have been identified in the human genome. As it
turns out, different cancers produce unique microRNA strands, and numerous
techniques for detecting them have been developed. Of those, most involve the
lengthy process of isolating and purifying RNA from blood or tissue samples
first, before the microRNA can be characterized.
"Detecting microRNA from a blood sample would be much more
efficient," Doyle says. Not to mention faster, and with cancer, time is of
the essence.
The MIT technology uses microscopic hydrogel particles around 200
micrometers in length, each one studded with literally millions of identical
DNA snippets. (Hydrogels are cross-linked, water-absorbing polymers that have
an affinity for nucleic acids, the building blocks of both RNA and DNA).
Attached to every piece of DNA is a short sequence that will bind to a
fluorescent probe, which is added later in the process.
To perform a blood serum assay, a mixture of particles are added to
a 25 microliter droplet. If there's any microRNA present, it binds to its
complementary DNA strand. The fluorescent probe is then added and the
researchers employ a custom-made microfluidic scanner to measure each
particle's fluorescence. Individual particles are also imprinted with a
chemical "barcode" that identifies the strand of microRNA being
detected. From start to finish, a sample can be assessed in less than three
hours.
"This approach is 100 times more sensitive than other particle
technologies for detecting microRNA," Doyle notes.
In fact, with its ability to sense as few as 10,000 strands of a
specific microRNA, this new hydrogel technique yields more reliable results
than other currently available procedures which utilize fluorescent probes as
labels. That's good news, especially since speed and accuracy are both valuable
traits in the realm of cancer detection. The company Doyle co-founded, Firefly Bioworks is
working to perfect a device for commercial use.
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