MIT Implant Monitors for Cancer and Heart Attacks

The sensor consists of a reservoir containing MRSw particles enclosed by a size-exclusion membrane. T2 changes are produced when analytes diffuse across the membrane and initiate particle aggregation.

During about 30 percent of all heart attacks, the patient experiences no symptoms. However, unmistakable signs of the attack remain in the bloodstream for days. MIT researchers, working with Massachusetts General Hospital’s Cardiovascular Research Center, have now designed a tiny implant that can detect those signs, which could help doctors more rapidly determine whether a patient has had a heart attack. The technology could also be adapted to monitor cancer and other diseases.

Singularity hub has coverage These implants aren’t ready for the clinic but the lead researcher Cima thinks 5 years for some applications. If MIT continues to see good results with these early prototypes, there’s a good chance we’ll see similar devices in clinical trials in the near future. Cima thinks that such experiments could be as little as five years away. The lowest hanging fruit are implants that could monitor for pH levels – acidity is often a hallmark of cancer cells. After that, we may see versions that can accurately detect hormone levels and drug responses.

In a study of mice, the team showed that the new implants can detect three proteins whose levels spike after a heart attack. Such devices could be used to monitor patients who are at high risk of heart attack, allowing doctors to respond more quickly if an attack occurs, preventing more severe heart disease from developing.

Most surprisingly, the researchers discovered that the sensors not only detect the proteins, they also reveal how much protein has ever been present. This is useful because it allows biomarkers (biological molecules that indicate a disease state) to be detected even if they are no longer in the bloodstream, says Michael Cima, professor of materials science and engineering and senior author of a paper on the work appearing in the Feb. 13 issue of Nature Biotechnology.

Nature Biotechnology – Implantable magnetic relaxation sensors measure cumulative exposure to cardiac biomarkers

The small disk-shaped implant, which is 2 millimeters thick and 8 millimeters wide, contains iron-oxide particles coated with antibodies that target a specific biomarker. A semi-permeable membrane allows the protein targets to enter the device, where they bind to the antibodies. In this study, the researchers implanted six sensors — two for each heart-attack biomarker — under the skin of each mouse, and read them using magnetic resonance imaging (MRI).

One important finding is that all three sensors’ output was shown to be proportional to the size of the damage to the heart, says Huang. Thus, not only can they potentially be used to detect a heart attack, but they could yield some quick information on its severity.

This study marks the first time anyone has used implantable sensors to detect three different biomarkers, says Lee Josephson, associate professor at MGH’s Center for Molecular Imaging Research. “This shows how generalizable this technique is,” says Josephson, who was not involved in this study. Potential applications include not only detecting heart disease and cancer, but also tracking glucose levels in diabetic patients, he says.

Cima is now developing an implant that measures pH (acidity level), which could be useful for detecting heart disease or cancer. (Tumors are more acidic than healthy tissue, and dramatic increase in acidity is a near-instantaneous indicator of heart attack.)

In the future, he hopes to modify these sensors to detect low levels of hard-to-detect bacteria or viruses, or migrating tumor cells. “This may be a way to look for extremely small, or extremely transient concentrations of biological markers,” he says.

The current version of the implant is usable for about two months, but Cima believes the devices could be made to last longer by using antibodies that don’t break down as quickly.

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