On January 5, 2005, in Diagnostics
Imaging down to the molecular and even the atomic level has been much in the news lately. For instance, a new MRI can detect atoms of various elements in the brain. It will help in the early diagnosis of brain disorders and in measuring the effect of drugs used to treat the conditions. There’s also a nanoscale biosensor that can detect single molecules of a substance. It could be in use in five to ten years.

Then there’s a non-radioactive contrast agent under development for molecular imaging of unstable plaque. It could also carry a drug to eliminate the plaque it finds. Finally, a nanotech-based device for detecting cancer at its earliest — molecular-level— stage could be ready within a decade. 

Other diagnostics-related news:

Another Stomach Turner

Italian researchers have developed a technique to robotically mimic the movement of sea worms with peduncles enabling them to move easily in very wet environments where there is solid and semi-solid material – such as the human intestine.

Reference: Unknown (2004). “Italians Build Robot ‘Worms’ for Soft Colonoscopy.” AGI Online, December 27.

Leading-edge MRI

With an especially strong magnet, an MRI scanner developed by GE Healthcare for the University of Illinois at Chicago can pick up the weak signals from atoms of sodium, phosphorus, oxygen, and other elements in the brain. It could enable earlier diagnosis of conditions such as Alzheimer’s and precisely and directly measure the effects of drugs on the brain. Tests of the MRI on human subects were planned to begin at the end of 2004.

Reference: Unknown (2004). “Super Scanner.” Technology Review, December.


Researchers from the University of Illinois at Urbana-Champaign have developed carbon nanotube sensors whose fluorescence diminishes when they come into contact with single molecules of a target substance. The fluorescence is persistent, allowing information to be gathered from its wavelength and intensity. A proof-of-concept system detected glucose levels in a sample of blood.

Reference: Unknown (2004). “Coated Nanotubes Make Biosensors.” Technology Research News, December 16.

Molecular Imaging

A small biotechnology company is working with a pharmaceutical giant to develop MRI contrast agents to identify unstable arterial plaque that can break off and may be responsible for 50 to 85 percent of fatal heart attacks. Conventional MRI can see reveal a buildup of plaque but not its stability.

The new contrast agent, a nanoscale droplet of chelated gadolinium, lipids, perfluorocarbon, and targeting ligands, selectively sticks to damaged plaque and shows up clearly in an MRI scan. It could lead not only to a better understanding of the role of unstable plaque, but also to treatments tailored to the individual patient. It will also be safer than an alternative molecular imaging agent — radionucleotides — because it is not radioactive and is eliminated naturally by the body.

The biotech firm is simultaneously working on a drug to eliminate the plaque. It may be ready for clinical trials in 2007. The same molecule that delivers the contrast agent would also carry the drug to where it’s needed. The strategy might work with cancer, too, so both companies are developing a contrast agent to find tiny tumors and a drug to kill eliminate them.

Reference: Savage, Neil (2004). “Seeing Heart Disease More Clearly.” Technology Review, November 29.

Nanodetector for Cancer

A Caltech researcher is building banks of silicon nanowires, each sensitive to a specific cancer-related protein, to detect cancer at the molecular level in a drop of blood or a tiny tissue sample. The nanosensors would be more accurate, cheaper, more convenient, and give much earlier warning than today’s primitive tests such as simple physical exams, mammography, x-rays, and current slow, costly, and unreliable blood tests that exist for only a few cancers anyway.

The researcher has the support of systems biology’s top gun, Leroy Hood, of the Institute for Systems Biology which is identifying the genetic and proteomic fingerprints of diseased cells. Hood’s team has already identified 300 cancer marker genes that are uniquely expressed in the prostate. The nanowire detector will be essentially the fingerprint reader.

The device has so far succeeded in detecting just a few molecules, and might eventually be able to detect individual molecules. Several technical problems remain to be overcome before the device can be made ready for use in the clinic. That could take up to a decade.

Reference: Ball, Philip (2005). “Dr. Nanotech vs. Cancer.” Technology Review, February.

Brain-Machine Interface

The BrainGate brain chip — currently enabling one quadriplegic patient to do e-mail, change TV channels, turn on lights, play Tetris, and move a robotic hand just by thinking — is not the only game in town, reports Kristen Philipkoski. “Other researchers are working on simpler, noninvasive BCIs” (brain-computer interfaces), she writes.

One is a noninvasive electroencephalogram, or EEG, cap that may pick up brain signals at least as well as the BrainGate implant, but much more research and testing will be needed to determine the limits of each approach.

A potential advantage of noninvasive BCIs could lie in their ability to retrieve signals from many points in the brain, whereas implanted chips can only cover a small, specific site and therefore only control a limited number of functions, such as motor movements. The external approach could be applied to broader, higher level cognitive tasks.

Neural Signals has an FDA-approved BCI that employs a small screw inserted 2 mm beneath the skull. The $50,000 device (including about $30,000 for surgery) is intended primarily for patients who are “locked-in” and have no movement at all, such as people with ALS. The device allows patients to move a cursor and turn a switch on and off.

BrainGate’s maker Cyberkinetics has plans for a prototype that would be implanted behind the ear and attach to external equipment via a magnet, so patients would not have a device protruding through their skin.

Reference: Philipkoski, Kristen (2005). “Patients Put on Thinking Caps.” Wired News, January 14.

Another New Birthing Simulator

Johns Hopkins University researchers have developed a new birthing simulator with a maternal pelvis with simulated soft tissue and sensors on the model fetus that report the forces being exerted on it. It is intended to be most helpful in preparing physicians for rare complications such as shoulder dystocia they otherwise might not encounter until a real emergency occurs.

Reference: Dollarhide, Maya (2005). “Birth Right.” Technology Review, January 6.


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