Microchip Helps Detect Cancer Cells
3/2/2011 by: Darleen Hartley
A micro nuclear magnetic resonance (microNMR) chip uses magnetic nanoparticles to measure protein levels to detect specific markers that indicate the presence of cancer. An app presents a readout on the phone’s display within an hour.
A small biopsy via fine needle aspiration takes cells from suspicious areas of the patient’s body. A combination of four protein markers detected cancer in 96 percent of the 50 patients with suspected malignancies in their lungs, colon, pancreas, liver or breasts. This compares to the standard pathology testing doctors currently use which is only 84 percent accurate, and takes three days longer to complete – which can be a lifetime for persons waiting to learn if they have cancer.
The professionals at the Center for Cancer Research at Massachusetts General Hospital (MGH) in Boston strive to understand cancer at a molecular level and to apply what they learn to improve treatment and prevention of cancer. The center is the largest hospital-based research program in the United States.
One of the researchers and coauthor of an article in Science Translational Medicine, Jered B. Haun, PhD, said: "False negatives and non-diagnostic samples are both at higher incidence with standard pathology. Since the [microchip-tested] sample size is so small, we take small aspirants of different areas of the tumor... to get a more global view of the results,"
The team is trying to make cancer detection less invasive than the large tissue samples now necessary. Dr. Cesar Castro, co-author of the paper explains: "Tumors are not ‘clean’ - you get inflammatory cells and other non-tumorous cells intertwined. And you get different numbers of cells in each sample." The diagnostic magnetic resonance device (DMR) requires much smaller samples than the traditional biopsy.
The DMR device created by Ralph Weissleder’s laboratory at the Center for Systems Biology at MGH combined with a smartphone notification isn’t the magic bullet however. The elusive and short-lived markers aren’t always present in cancer cells and must be analyzed immediately after extraction.
Hakho Lee, assistant professor who spearheaded development of the system, indicated that they used a novel labeling chemistry. The research involved trial and error using a panel of 12 cancer markers which were whittled down to analysis of a specific four-marker combination that could detect cancerous cells in patient samples with almost 100 percent accuracy.
The DMR is essentially composed of two parts: one that holds antibodies targeted for specific cellular markers of cancer, and one that holds tiny signal-generating magnetic particles. This miniaturized DMR device consists of an NMR probe containing microcoils for both radio-frequency (RF) excitation and NMR signal detection, on-board NMR electronics, a microfluidic network for sample handling, and a small permanent magnet for generating an external magnetic field.
When the system is ready to go to market, it should be reasonably priced. "Like cell phones in general, the more you make, the cheaper they get. It's not an expensive device at all," Haun said.
DMR, NMR, Ralph Weissleder, Massachusetts General Hospital, Cesar Castro, Hakho Lee, MRI, magnetic resonance, biology, cancer, Jered B. Haun, nuclear magnetic resonance, Boston, radio frequency
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