24932 PSA

http://www.technologyreview.com/biomedicine/24932/

Prostate Cancer Results While You Wait

A new microfluidics device gives results in 15 minutes.

WEDNESDAY, MARCH 31, 2010

Detecting cancer: Claros Diagnostics has developed a microfluidics cartridge and reader (above) designed to detect PSA levels in prostate cancer patients in just 15 minutes.

Credit: Claros Diagnostics

Wednesday, March 31, 2010

Prostate Cancer Results While You Wait

A new microfluidics device gives results in 15 minutes.

By Emily Singer

In an office park in Woburn, MA, a volunteer presents his fingertip for a quick finger stick. A phlebotomist wicks up the small drop of blood with a specially made square of plastic, then snaps the plastic into a credit-card sized microfluidics cartridge and feeds it into a special reader. Fifteen minutes later, the device spits out the volunteer's prostate specific antigen (PSA) level, a protein used to monitor the return of prostate cancer after treatment.

The rapid results are possible because of a novel microfluidics technology developed by startupClaros Diagnostics, which hopes to make quick PSA screening in the doctor's office a reality. If approved by the U.S. Food and Drug Administration, the device will be one of the first examples of long-awaited microfluidics-based diagnostics tests that can be performed in the hospital or doctor's office. While microfluidics--which allows for the manipulation of fluids on a chip at microscopic scales--has been around for a decade, the complexity and expense has kept it largely limited to research applications.

Claros's technology, which consists of a small blood-collector device, a disposable cartridge, and a toaster-sized reader, could, in theory at least, be adapted to detect any number of different proteins. But the company has initially chosen to focus on PSA, which is routinely screened. With current testing, blood samples are typically sent to a centralized lab for PSA analysis. Results are returned in a day or two. Claros's test, now in clinical trials, would allow PSA readings to be determined during the patient's visit.

"Having a quick PSA test that is accurate would certainly be helpful to most urologists--simple and inexpensive being the two key words," says Jerome Richie, chief of urology at Brigham and Women's hospital in Boston. But he says that such a test must be able to accurately analyze the low levels of PSA that are present after prostate surgery.

Key to Claros's device is its ability to perform the test on a small drop of blood. The surface of the cartridge is covered in narrow channels, which serve as both storage for the chemicals needed for the assay and as tiny test tubes in which to carry out the reaction. Each reagent is lined up sequentially in one long channel and separated by small air bubbles. Once the cartridge is inserted into the reader, a vacuum pulls the blood through one channel and delivers the appropriate sequence of reagents. This approach avoids the pumps used to move chemicals in other microfluidics chips, enabling a simple and robust design with no moving parts. The reader itself is simple, using an LED and photodiode to detect the buildup of silver--the output of the reaction--on the cartridge. The more silver, the less light passes through the chip and the higher the PSA level.

Scientists at Claros developed proprietary injection molding technologies that permit the hard-plastic cartridges to be made very quickly, in about 15 seconds, and for about 10 cents apiece. "Injection molding is used to make lots of consumer products, like pens, but we can manufacture them to micron-sized resolution," says Samuel Sia, one of Claros's cofounders and a bioengineer at Columbia University. "They cost just a few cents, and we can make hundreds of thousands per year--not many people can do that."

Claros is currently running clinical trials to compare its device to standard PSA testing methods in order to garner regulatory approval. If approved, it could make a prostate-cancer patient's visit to the doctor's office much more productive. According to Stephen Zappala, a urologist at the Lahey Clinic in Andover, MA, who is working with Claros on the clinical trials, "the Claros technology will dramatically increase the efficiency of the urologist's practice and alleviate patient anxiety associated with waiting for a laboratory result."

Vincent Linder, a cofounder and chief technology officer, says Claros expect results from the trial in the next few months. The company hopes to launch the device in Europe later this year and in the United States in 2011. Similar technology could be used to create screening panels for women's health or cardiac health, though Linder declined to discuss specific plans. He also declined to give an estimate of the system's price.

In addition to the PSA monitoring device, which will be marketed in the U.S and Europe, Sia is developing a second version of the system to screen for infectious diseases in poor countries. While it uses the same core technology, this version has a battery-powered reader about the size of an iPhone and is designed to detect HIV, syphilis, and hepatitis. The device is currently being tested in health-care centers in Rwanda that treat pregnant women. "If you catch the diseases in mothers, you can prevent transmission to newborn, increasing clinical impact," says Sia. After a series of successful field trials, Sia is now trying to find funding to move the device through the regulatory process in Africa.