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from the theirs-gold-in-them-thar-prostates dept.
A test that costs less than a $1 and yields results in minutes has been shown in newly published studies to be more sensitive and more exact than the current standard test for early-stage prostate cancer.
The simple test developed by University of Central Florida scientist Qun "Treen" Huo holds the promise of earlier detection of one of the deadliest cancers among men. It would also reduce the number of unnecessary and invasive biopsies stemming from the less precise PSA test that's now used.
When a cancerous tumor begins to develop, the body mobilizes to produce antibodies. Huo's test detects that immune response using gold nanoparticles about 10,000 times smaller than a freckle.
When a few drops of blood serum from a finger prick are mixed with the gold nanoparticles, certain cancer biomarkers cling to the surface of the tiny particles, increasing their size and causing them to clump together.
Among researchers, gold nanoparticles are known for their extraordinary efficiency at absorbing and scattering light. Huo and her team at UCF's NanoScience Technology Center developed a technique known as nanoparticle-enabled dynamic light scattering assay (NanoDLSay) to measure the size of the particles by analyzing the light they throw off. That size reveals whether a patient has prostate cancer and how advanced it may be.
And although it uses gold, the test is cheap. A small bottle of nanoparticles suspended in water costs about $250, and contains enough for about 2,500 tests.
http://www.nanowerk.com/nanotechnology-news/newsid=39654.php
[Source]: http://today.ucf.edu/cheap-prostate-cancer-test-better-than-psa/
[Abstract]: http://pubs.acs.org/doi/abs/10.1021/acsami.5b00371
(Score: 2) by kaszz on Sunday April 05 2015, @05:31PM
So it seems the method is to emit coherent light (laser) into a sample and then measure the amplitude of that light at specific angles?
If so, it makes me wonder how one can be so sure of a connection between amplitude at an angle and specific antibodies?
Btw, do you happen to know how to make it possible to tune a laser into emitting different wavelengths? kind of dial-a-wavelength-laser for measurement purposes.
(Score: 3, Informative) by Rich on Sunday April 05 2015, @06:22PM
So it seems the method is to emit coherent light (laser) into a sample and then measure the amplitude of that light at specific angles?
Yes.
If so, it makes me wonder how one can be so sure of a connection between amplitude at an angle and specific antibodies?
With nephelometric measurements usually an agglutination "amplifier" is used. I know that latex particles are being used, while the assay in the article topic uses gold nanoparticles for this. As antigen/antibody reacts, it somehow (don't ask me about the details) clumps together the particles (described for gold in the abstract). The bigger the blobs being held together, the bigger the light scattering. This works with surprising precision. Repeatibilty is around 1% in a sound setup.
I'm not deep enough in the biochemistry to completely understand whether the gold particle agglutionation has any specific advantages over the usual tumor marker tests done today. The article claims advantages over a biopsy but IgG already is a usual component of a tumor marker test panel. I'd have to ask some assay development boffins.
do you happen to know how to make it possible to tune a laser into emitting different wavelengths?
Well, duh, that would be a "tunable laser". It has its own Wikipedia entry. Interestingly enough, different wavelengths are often used for "regular" photometric measurements, but I'm not aware that this is done for nephelometry. However, the practical approach would probably be to use separate lasers in different wavelengths to take any possible inaccuracy from the (analog) tuning process out.