2008年12月3日 星期三

抽血檢測早期癌症大突破


好多年前大女兒在麻省理工學院就是在研究如何檢測血液而發現早期癌症。當年發現孕婦的身體與常人不太一樣。抽血檢測早期癌症的結果與常人的結果混淆。又因為是團體研究不是個人成果。也因此無法提出論文參加西屋科技比賽。當時很梗梗於懷。現在看到這新聞就特別仔細再看幾次了。

圖為史丹福磁性奈米科技中心主任王善祥,他的研究成果受矚目。圖由史丹福大學提供

檢測早期癌症 王善祥大突破
史大團隊研發血液檢測晶片 運用磁性奈米技術 提早發現癌蹤 提早治療



圖為生物檢測晶片快速檢測癌症成果,刊登美國國家科學院期刊。圖由史丹福大學提供
【記者吳日君加州史丹福2日報導】由史丹福大學材料科學與工程系華裔教授、史丹福磁性奈米科技中心(Stanford Center for Magnetic Nanotechnology)主任王善祥(Shan Xiang Wang)領軍的研究團隊研發出一種血液檢測晶片裝置(MagArray Biodetection Chips),可協助尋找血液流向的早期癌症所在,以此進行早期治療、提高存活率。這項新研究成果本周登上「美國國家科學院期刊」(Proceedings of the National Academy of Sciences)線上版。
這項以血液檢測晶片裝置系統,通過對血液樣本的檢測就可以診斷體內是否存在癌症相關蛋白,檢測過程不到1小時即可完成,優於現存所有已商業化的檢測裝置。系統主要技術是運用磁性奈米技術 (magnetic nanotechnology)以找到癌蛋白,比其他裝置更敏銳,因為癌蛋白僅能在少數血液流中被發現。

王善祥表示,研究證明此種晶片裝置與檢測可找到多種生化標記,效果優於現存已商業化產品。他認為,這項研究將於2-3年內可用於檢測早期癌症,協助醫生選擇更有效的治療方法;因為越早發現癌症,越有機會進行治療,特別是在肺癌、卵巢癌和胰臟癌,這些癌症藏在身體內部、不易被發現。

新晶片裝置可同時檢測不同種類癌蛋白,王善祥指出,研究人員目前仍不確定何種癌症標記是用於診療的最佳標記,此外,檢測多種生化標記可讓醫生更容易診斷病人罹患何種特定癌症。這項癌蛋白讀取裝置也是全球現存手持裝置中,體積最小的。

他的研究團隊運用磁性奈米技術,利用一般材料多半不帶磁性的特點,尋找稀少的磁信號。這種搜索像夜空中搜尋清晰可見的煙花一樣方便,而且更快、靈敏度更高,可以清楚檢測出小單位的癌症蛋白。

由於這項檢測產品還須經過相關測試,包括臨床試驗等法令相關規定測試,必須在醫院或私人診療實驗室進行,王善祥在矽谷共同創辦初創公司「MagArray」,將進行臨床試驗來檢測癌蛋白。也將進行實驗來測試此晶片裝置未來是否能用於急診室中病人因胸痛而須快速檢測心臟病。因心臟病產生時,心臟細胞壞死與特定生化蛋白標記有關。

2008-12-03
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http://news-service.stanford.edu/news/2008/december3/cancer-120308.html
Stanford Report, December 1, 2008
Stanford blood scanner detects even faint indicators of cancer

BY DAVID ORENSTEIN
A team led by Stanford researchers has developed a prototype blood scanner that can find cancer markers in the bloodstream in early stages of the disease, potentially allowing for earlier treatment and dramatically improved chances of survival.

The system based on MagArray biodetection chips can find cancer-associated proteins in a blood serum sample in less than an hour, and with much greater sensitivity than existing commercial devices. In fact, the device, which uses magnetic nanotechnology to spot the cancer proteins, is tens to hundreds of times more sensitive, meaning the proteins can be found while there are relatively few of them in the bloodstream. The researchers reported their results in the Dec. 1 online edition of the Proceedings of the National Academy of Sciences.

"This is essentially a proof-of-concept study showing that now we have a chip and a reader that can find multiple biomarkers in a sample at a concentration much lower than the standard that is commercially available," said Shan Wang, a Stanford professor of materials science and of electrical engineering.

Wang is optimistic that the technology will someday save lives by detecting cancer early or by helping doctors select more effective therapy. "The earlier you can detect a cancer, the better chance you have to kill it," he said. "This could be especially helpful for lung cancer, ovarian cancer and pancreatic cancer, because those cancers are hidden in the body."

Wang is a senior author of the paper, along with Stanford biochemistry and genetics Professor Ronald W. Davis of the Stanford Genome Technology Center and University of California-Santa Cruz biomolecular engineering Professor Nader Pourmand.

The device is able to detect many different kinds of proteins at the same time, which is important for two reasons, Wang said. First, researchers are still uncertain which cancer biomarkers are the best diagnostic indicators. Second, detecting multiple biomarkers simultaneously will allow a doctor to diagnose more specifically the kind of cancer a patient may have.

Wang says the handheld device could be the smallest protein array reader in the world.

By means of magnets
The specialty of Wang's research group at Stanford is magnetic nanotechnology. Magnetism is rare in biological systems, so any magnetic signal in a blood serum sample stands out like a flare in the night sky. By tagging cancer proteins with tiny magnetic particles, rather than electrically charged or glowing particles as in other detectors, the new system can obtain a clearer signal from a smaller number of cancer proteins.

At the heart of the detector is a silicon chip, designed by the paper's lead author, Sebastian Osterfeld, a Stanford doctoral student in materials science and engineering. The chips have 64 embedded sensors that monitor for changes in nearby magnetic fields. Attached to these sensors are "capture antibodies," painstakingly selected by Heng Yu, formerly a postdoctoral fellow at the Stanford Genome Technology Center, and Richard Gaster, a student in a combined program of doctoral and medical degrees.

The sensor's "capture antibodies" grab specific cancer-related proteins as they float by and hold onto them. Then a second batch of antibodies is added to the mix. They latch onto magnetic nanoparticles as well as the cancer biomarkers that are being held captive by the sensors. Thus when the MagArray sensors detect the magnetic field of nanoparticles, they've found cancer markers as well.

In the paper, the researchers estimate that they could detect levels of the human chorionic gonadotropin protein at a level about 400 times lower than the level required for detection by current commercial kits known by the acronym ELISA, in which captured cancer proteins are tethered to color-altering or fluorescent labels.

At Stanford Medical Center, the detector is viewed as a potentially significant clinical advance, according to a diagnostics expert there.

"This work represents a giant leap forward in enabling technology for in vitro protein diagnostics with significant potential for many applications including cancer detection and management," said Dr. Sam Gambhir, the principal investigator of the Center of Cancer Nanotechnology Excellence at Stanford.

Headed for hospitals?
To properly prepare a patient's blood sample for use with the detector, a technician must use a centrifuge to separate out the serum, which contains the biomarkers. For this reason, the device must be located in a hospital or a private diagnostic lab, Wang said. But before then it must face clinical testing and trials to win regulatory approval. To see the detector through those steps, Wang has co-founded a startup company, MagArray Inc., in the Panorama Institute for Molecular Medicine, a not-for-profit incubator in Sunnyvale, Calif.

The nascent startup is also investigating the possible use of the detectors in emergency rooms to quickly check for heart attacks when patients arrive with chest pains. Like cancer, heart cell death is associated with the release of specific biomarker proteins.

The research was funded partly by grants from the U.S. National Institutes of Health, the National Science Foundation and the Department of Defense. Other authors on the paper include Stefano Caramuta, Liang Xu, Shu-Jen Han, Drew Hall, Robert Wilson and Robert White, all of Stanford, and Shouheng Sun of Brown University.

David Orenstein is the communications and public relations manager for the Stanford School of Engineering.


Related Information
Center for Magnetic Nanotechnology
Shan Wang

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