On November 6, 2005, in Diagnostics
Several variations on the Star Trek non-invasive, handheld, diagnostic “tricorder” theme have been reported in past issues (and we’ve just mentioned another, in the Devices section). Here’s another version anyone can use — doctor not needed. For the moment, however, doctors will be needed to use nanowire arrays developed at Harvard to detect a cancer and its stage in a few minutes from a pinprick of blood, but doctors might be wise to note that microfluidic labs-on-a-chip, that do essentially the same as the nanowire arrays, are at about the same stage of development as silicon chips were at the dawn of personal computing, and the prognosis is that we’ll be seeing the diagnostic equivalent of Apple IIs and IBM PCs in the home medicine cabinet within a few years. They may even be powered by the biofluid they are testing.

Other developments in diagnostics:

  • Smart new algorithms applied to data from an old technology are showing promisein detecting early stage Alzheimer’s, depression, and the effect of antidepressants on a patient.
  • Nanotechnology applied to an MRI contrast agent made it less toxic and far more sensitive.

The Eyes Have It

Source article

A prototype Optical Scanning Instrument (OSI) takes snapshots of the inside of a patient’s eye, which are then analyzed by algorithms adapted from work commissioned by the US Defense Advanced Research Projects Agency (DARPA) to compare variations in eye movements, pupil size, retinal blood vessels, infections, and corneal abnormalities to a disease database that relates those attributes to diseases, to see if there is a match to a particular illness.

DARPA’s algorithms can already indicate exposure to toxins and the presence of head trauma, carbon monoxide, cyanide, high blood pressure, diabetic retinopathy, and some neurological disorders. The company developing OSI hopes to extend them to a whole host of substances and conditions — including cocaine, alcohol, malaria, botulism, AIDS, syphilis, Lyme disease, leukemia, lymphoma, Stevens-Johnson syndrome, sickle cell anemia, chicken pox, bleeding or clotting disorders, congestive heart failure, arthrosclerosis, high and low cholesterol, and even pregnancy, premature births, and malnutrition — all of which are revealed in the eyes.

The company hopes to turn its prototype into a mass-produced diagnostic device, ultimately in the form of a handheld device “that practically anyone can use to diagnose serious illnesses.”

Nanodetector for Cancer

Source article

Harvard University researchers have created a nanowire array that can identify many different cancer markers in a mere pinprick of blood in a matter of minutes. Each nanowire has antibody receptors for specific cancer markers (proteins) — such as prostate specific antigen (PSA), PSA-a1-antichymotrypsin, carcinoembryonic antigen and mucin-1. When a protein in the blood slots into its receptor on the electrified nanowire, for a characteristic length of time before dislodging, the wire’s conductance changes, alerting the researcher that the cancer marker is present in the blood. The lead researcher said the arrays can distinguish among cancer marker molecules with “near-perfect selectivity.”

With the detection technique (i.e., nanowire arrays) ready, what is needed next is the discovery of more cancer markers for them to detect; in particular, the multiple biomarkers thought to be involved in complex diseases (like cancer) for which tests of single markers are insufficiently robust for diagnosis of the disease and its stage of pathogenesis — important both for early detection and for tracking the disease during treatment.

The arrays could be used in a physician’s office, without any need for biochemical manipulation.

Lab On a Chip

Source article

“This little piece of glass and polymer replaces what goes on in about a quarter of my research lab and it actually, I think, will change our lives — not just the lives of sick people, but healthy people as well,” a cancer researcher at the University of Alberta is quoted as saying in a university press release. She is referring to a microfluidic chip that is doing work that previously took a quarter of her entire laboratory.

The work is the formerly complex and expensive testing of samples for the presence of cancer, and the work going on in the remaining three-fourths of the lab includes developing further innovations of lab-on-a-chip technology. The center of which the lab is a part wants “to do to the life sciences what has been done to electronics. We expect to see the same evolution that led from a million-dollar computer to something of the same power on your wristwatch for a couple of dollars. That’s made computers accessible to all, now we want to do that for the rest of the human population with something more important than moving electrons around.”

Three tests have already been successfully adapted to the lab-on-a-chip. The first, a genetic test to determine how a patient with childhood lymphocytic leukemia will respond to specific treatments, is about to undergo clinical trials. The second will detect chromosomal abnormalities in molecular myeloma and follicular lymphoma, two diseases of the immune system, and alert doctors to avoid conventional chemotherapy for these patients and stem cell transplants which don’t seem to work, but focus instead on new biological therapies that are more likely to work. The third test detects high viral loads in urine samples.

“Imagine,” says a university official, “a Canada where complex medical test results are available almost instantly, where aging Canadians can perform home-based testing with almost instantaneous transmission to a doctor’s office, where emerging or relapsing cancer can be rapidly detected in local healthcare centres, where high quality healthcare is easily available on the farm, in the mountains, on the high Arctic tundra, or even in outer space.”

Indeed. But don’t stop at Canada.

Urine-powered Diagnostic Chips

Source article

Physicists in Singapore have made “the perfect power source” for cheap, disposable, biochips to test for diabetes and other diseases, says an article on PhysOrg.com. It is a paper battery and it uses the fluid being tested (urine, or perhaps some other biofluid) as the power source for the device doing the testing.

The battery is made from a layer of paper steeped in copper chloride (CuCl) and sandwiched between strips of magnesium and copper. The whole is then laminated. It measures slightly smaller than a credit card. Using 0.2 ml of urine, it generated 1.5 V and 1.5 mW of power.

Alzheimer’s and Depression Diagnosis

Source article

Early results from clinical trials of a brain-wave analysis system indicate that it can accurately diagnose early-stage Alzheimer’s disease and can help to diagnose depression. The system converts EEG (electroencephalogram) into a numerical value between 0 and 100 indicating the amount of electrical brain activity.

One of three trials correlating reduced brain-wave activity with an EEG showing early signs of Alzheimer’s, performed at McLean Hospital and Harvard Medical School, found the device identified Alzheimer’s patients with 81 percent accuracy. A second test is underway among150 senior citizens to confirm the preliminary results.

At least one expert, quoted in a Wired News article, was skeptical of the results, because EEG is old technology and even modern positron emission tomography and functional magnetic resonance imaging haven’t been up to the task.

But if that expert is wrong and the system does indeed work, the icing on the cake is that the basic technology is already in use in 40 percent of US operating rooms to guard against patients waking up during procedures, and is also integrated into medical devices from Philips, General Electric, and others.

There is even more potentially good news. The technology, slightly modified to measure subtle shifts between the brain hemispheres, has diagnosed increased suicidal thoughts with 76 percent accuracy, and has also detected if an antidepressant medication is working after only one week.

Gadonanotube MRI Contrast Agent

Source article

The most widely used dyes used to enhance the contrast in about 30 percent of all MRI scans contain the toxic metal gadolinium. When US and Swiss researchers encased gadolinium atoms in carbon nanotubes they found their “gadonanotubes” not only eliminated the toxic effects but also were at least 40 times more effective than the best contrast agents currently in clinical use.

The researchers plan to attach disease-specific antibodies and peptides to gadonanotubes so they can be targeted to cancerous tumors and other diseased cells.


Leave a Reply

Your email address will not be published. Required fields are marked *