$1 Gold Nanoparticle Test Outperforms PSA Screening

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 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. The results were published in the journal ACS Applied Materials & Interfaces.
 
When a cancerous tumor begins to develop, the body mobilizes to produce antibodies. The 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. The researchers 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.
After lung cancer, prostate cancer is the second-leading killer cancer among men. The most commonly used screening tool is the PSA, but it produces so many false-positive results - leading to painful biopsies and extreme treatments - that one of its discoverers recently called it "hardly more effective than a coin toss."
 
Pilot studies found the new technique significantly more exact. The test determines with 90 to 95 percent confidence that the result is not false-positive. When it comes to false-negatives, there is 50 percent confidence - not ideal, but still significantly higher than the PSA's 20 percent - and the researchers are working to improve that number.
 
The researchers are also researching the technique's effectiveness as a screening tool for other tumors.
Their goal is to have a universal screening test for cancer.
 
Based on material originally posted by University of Central Florida.