 |
CHICAGO, Jan. 7, 2004 — Nanosphere Inc., a privately held life sciences company with headquarters in Northbrook, Ill., is adding protein detection capabilities to its line of nanotech-based molecular detection tools.
Developed by Northwestern University researcher and Nanosphere co-founder Chad Mirkin, the new technique uses gold nanoparticles and short strands of “barcode” DNA to detect the presence of disease-specific molecules in the human body.
Many human diseases are accompanied by telltale “biomarker” molecules. One example is the prostate-specific antigen (PSA), a protein that crops up in the bodies of men with prostate cancer. In recent years, diagnostic laboratories have developed methods for detecting PSAs and other biomarkers.
 |
The system works by exposing a biological sample — say, blood — to gold nanoparticles. Each particle is covered with snippets of “barcode DNA,” each engineered to have the same genetic sequence. Also attached to the particles are target-specific antibodies designed to bond with the target protein molecule. Antibody-bearing magnetic microparticles are then added to the sample, and a magnetic field is applied to separate out the barcode DNA. If the barcode sequence is detected at the end of the process, then the disease-specific protein was present in the sample.
“It appears that this is a truly interesting technology, with breakthrough potential,” said Girish Solanki, industry manager for Frost & Sullivan’s Technical Insights division.
The barcode technology expands on Nanosphere’s Verigene ID system, which the company launched in June. The result: “a unique platform technology that can do all three: DNA, RNA, and protein detection,” said Chief Operating Officer Vijaya Vasista.
She sees many applications for the technology, including ultra-sensitive detection of diseases such as AIDS and Alzheimer’s.
Early cancer detection is another application, but in the case of prostate cancer the technology falls short of a panacea. That’s because PSA levels can fluctuate in response to many different factors, ranging from normal variations in prostate activity to the presence of cancer and other diseases. A better use for the bio-barcode system may be to monitor recovering prostate cancer patients. After treatment, their PSA levels should stabilize at very low levels. Slight increases can mean trouble, and monitoring requires an extremely sensitive test.
PSA is also undergoing clinical testing as a marker for breast cancer. But in women it occurs at much lower levels than in men. If a connection is proven, bio-barcodes could prove a valuable diagnostic tool..
Nanosphere is “about a year away” from launching product for the molecular laboratory market, according to Vasista. Initially the company will push its DNA- and RNA-based assays, or tests for specific targets. Over time it will extend these offerings to include bio-barcode protein assays. “The single platform is very attractive because we can quickly migrate to proteins as that becomes more and more of a need.”
Vasista said the company will market its technology using the razor-and-razor-blade approach, with many different assays available on one platform. The gold nanoparticle probes, magnetic probes, substrates, and DNA barcodes will all be manufactured at Nanosphere’s Northbrook, Ill., facility.
Initially, the company plans to sell direct but will likely seek out a marketing partnership over time. “The big companies don’t want to take you on until you can prove you’ve got something that customers want,” she said. “Long term, in order to get real penetration into these markets, we envision partnering with someone who already has a dominant presence.”
Eventually Nanosphere’s bio-barcode technology could find its way into proteomics labs. “The more we learn about genetics — DNA and RNA — the more we’ll learn about proteins as well. So the market just continues to expand.”
Frost & Sullivan’s Solanki agrees that the technique is “a logical extension of Nanosphere’s core DNA detection technology.” Nanosphere sees biohazard detection systems for the government as another potential market.
Today, genomic and proteomic testing requires highly skilled technicians, and as demand for these tests increases, the field is facing a labor shortage. So ease-of-use was a key goal in developing the system. According to Vasista, Nanosphere set out to “make this kind of testing so simple — as we joke — that even a doctor can use it.”
The company also wanted more stability than today’s genomic detection technology can deliver. Standard fluorescence-based DNA signals can be destroyed by exposure to light, can fade over time, and sometimes face other issues, like auto-fluorescing. Vasista said Nanosphere’s system overcomes many of these problems. “Gold, as we well know, is highly stable.”
Frost & Sullivan’s Solanki notes other potential advantages: “It certainly is more efficient and less expensive than traditional methods [based on] fluorescence, but has to be proven robust enough in the long run. I certainly expect more from Nanosphere during the coming months.”