Study finds $1 test using gold nanoparticles outperforms PSA screen for prostate cancer.


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 and Florida Hospital Cancer Institute researchers 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 team state that the test is simple. It’s much better than the test currently available, which is the PSA, and it’s cost-effective.  The study is published in ACS Applied Materials & Interfaces

The researchers go on to explain that when a cancerous tumour begins to develop, the body mobilizes to produce antibodies. The test in the current study 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.

Previous studies have shown that gold nanoparticles are extremely efficient at absorbing and scattering light. The team 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.   With the team stating that the test’s impact is going to be big.

After lung cancer, prostate cancer is the second-leading killer cancer among men, with more than 240,000 new diagnoses and 28,000 deaths every year, state the researchers. 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.

The current study found that the team’s technique is 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.  The team are now working to improve the test’s already higher number.

The team are now pursuing more extensive clinical validation studies with collaborators. They hope to complete major clinical trials and see the test being used by physicians within three years.  The researchers are also researching their new technique’s effectiveness as a screening tool for other tumour-types.

The team state that potentially, this could be a universal screening test for cancer, adding that their vision is to develop an array of blood tests for early detection and diagnosis of all major cancer types.  These blood tests would all based on the same technique and procedure.

The team have now co-founded Nano Discovery Inc., a start-up company headquartered in a UCF Business Incubator, to commercialize the new diagnostic test.

Source:  University of Central Florida

 

When citrate ligands-capped gold nanoparticles are mixed with blood sera, a protein corona is formed on the nanoparticle surface due to the adsorption of various proteins in the blood to the nanoparticles. Using a two-step gold nanoparticle-enabled dynamic light scattering assay, we discovered that the amount of human immunoglobulin G (IgG) in the gold nanoparticle protein corona is increased in prostate cancer patients compared to noncancer controls. Two pilot studies conducted on blood serum samples collected at Florida Hospital and obtained from Prostate Cancer Biorespository Network (PCBN) revealed that the test has a 90–95% specificity and 50% sensitivity in detecting early stage prostate cancer, representing a significant improvement over the current PSA test. The increased amount of human IgG found in the protein corona is believed to be associated with the autoantibodies produced in cancer patients as part of the immunodefense against tumor. Proteomic analysis of the nanoparticle protein corona revealed molecular profile differences between cancer and noncancer serum samples. Autoantibodies and natural antibodies produced in cancer patients in response to tumorigenesis have been found and detected in the blood of many cancer types. The test may be applicable for early detection and risk assessment of a broad spectrum of cancer. This new blood test is simple, low cost, requires only a few drops of blood sample, and the results are obtained within minutes. The test is well suited for screening purpose. More extensive studies are being conducted to further evaluate and validate the clinical potential of the new test.  Gold Nanoparticle-Enabled Blood Test for Early Stage Cancer Detection and Risk Assessment.  Zhu et al 2015.

When citrate ligands-capped gold nanoparticles are mixed with blood sera, a protein corona is formed on the nanoparticle surface due to the adsorption of various proteins in the blood to the nanoparticles. Using a two-step gold nanoparticle-enabled dynamic light scattering assay, we discovered that the amount of human immunoglobulin G (IgG) in the gold nanoparticle protein corona is increased in prostate cancer patients compared to noncancer controls. Two pilot studies conducted on blood serum samples collected at Florida Hospital and obtained from Prostate Cancer Biorespository Network (PCBN) revealed that the test has a 90–95% specificity and 50% sensitivity in detecting early stage prostate cancer, representing a significant improvement over the current PSA test. The increased amount of human IgG found in the protein corona is believed to be associated with the autoantibodies produced in cancer patients as part of the immunodefense against tumor. Proteomic analysis of the nanoparticle protein corona revealed molecular profile differences between cancer and noncancer serum samples. Autoantibodies and natural antibodies produced in cancer patients in response to tumorigenesis have been found and detected in the blood of many cancer types. The test may be applicable for early detection and risk assessment of a broad spectrum of cancer. This new blood test is simple, low cost, requires only a few drops of blood sample, and the results are obtained within minutes. The test is well suited for screening purpose. More extensive studies are being conducted to further evaluate and validate the clinical potential of the new test. Gold Nanoparticle-Enabled Blood Test for Early Stage Cancer Detection and Risk Assessment. Zhu et al 2015.

 

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