Rachel Ehrenberg has written an Aug. 21, 2015 news item about the latest and greatest carbon nanotube-based biomedical sensors for the journal Nature,
The future of medical sensors may be going down the tubes. Chemists are developing tiny devices made from carbon nanotubes wrapped with polymers to detect biologically important compounds such as insulin, nitric oxide and the blood-clotting protein fibrinogen. The hope is that these sensors could simplify and automate diagnostic tests.
Preliminary experiments in mice, reported by scientists at a meeting of the American Chemical Society in Boston, Massachusetts, this week [Aug. 16 – 20, 2015], suggest that the devices are safe to introduce into the bloodstream or implant under the skin. Researchers also presented data showing that the nanotube–polymer complexes could measure levels of large molecules, a feat that has been difficult for existing technologies.
Ehrenberg focuses on one laboratory in particular (Note: Links have been removed),
“Anything the body makes, it is meant to degrade,” says chemical engineer Michael Strano, whose lab at the Massachusetts Institute of Technology (MIT) in Cambridge is behind much of the latest work1. “Our vision is to make a sensing platform that can monitor a whole range of molecules, and do it in the long term.”
To design one sensor, MIT researchers coated nanotubes with a mix of polymers and nucleotides and screened for configurations that would bind to the protein fibrinogen. This large molecule is important for building blood clots; its concentration can indicate bleeding disorders, liver disease or impending cardiovascular trouble. The team recently hit on a material that worked — a first for such a large molecule, according to MIT nanotechnology specialist Gili Bisker. Bisker said at the chemistry meeting that the fibrinogen-detecting nanotubes could be used to measure levels of the protein in blood samples, or implanted in body tissue to detect changing fibrinogen levels that might indicate a clot.
The MIT team has also developed2 a sensor that can be inserted beneath the skin to monitor glucose or insulin levels in real time, Bisker reported. The team imagines putting a small patch that contains a wireless device on the skin just above the embedded sensor. The patch would shine light on the sensor and measure its fluorescence, then transmit that data to a mobile phone for real-time monitoring.
Another version of the sensor, developed3 at MIT by biomedical engineer Nicole Iverson and colleagues, detects nitric oxide. This signalling molecule typically indicates inflammation and is associated with many cancer cells. When embedded in a hydrogel matrix, the sensor kept working in mice for more than 400 days and caused no local inflammation, MIT chemical engineer Michael Lee reported. The nitric oxide sensors also performed well when injected into the bloodstreams of mice, successfully passing through small capillaries in the lungs, which are an area of concern for nanotube toxicity. …
There’s at least one corporate laboratory (Google X), working on biosensors although their focus is a little different. From a Jan. 9, 2015 article by Brian Womack and Anna Edney for BloombergBusiness,
Google Inc. sent employees with ties to its secretive X research group to meet with U.S. regulators who oversee medical devices, raising the possibility of a new product that may involve biosensors from the unit that developed computerized glasses.
The meeting included at least four Google workers, some of whom have connections with Google X — and have done research on sensors, including contact lenses that help wearers monitor their biological data. Google staff met with those at the Food and Drug Administration who regulate eye devices and diagnostics for heart conditions, according to the agency’s public calendar. [emphasis mine]
This approach from Google is considered noninvasive,
“There is actually one interface on the surface of the body that can literally provide us with a window of what happens inside, and that’s the surface of the eye,” Parviz [Babak Parviz, … was involved in the Google Glass project and has talked about putting displays on contact lenses, including lenses that monitor wearer’s health] said in a video posted on YouTube. “It’s a very interesting chemical interface.”
Of course, the assumption is that all this monitoring is going to result in healthier people but I can’t help thinking about an old saying ‘a little knowledge can be a dangerous thing’. For example, we lived in a world where bacteria roamed free and then we learned how to make them visible, determined they were disease-causing, and began campaigns for killing them off. Now, it turns out that at least some bacteria are good for us and, moreover, we’ve created other, more dangerous bacteria that are drug-resistant. Based on the bacteria example, is it possible that with these biosensors we will observe new phenomena and make similar mistakes?