Blood tests usually involve drawing some blood out of the body. Now scientists from the Ecole Polytechnique Fédérale de Lausanne (EPFL) have developed an implant that allows blood to be analyzed from within the body, with results then transmitted wirelessly to a computer. While still at the experimental stage, the device could make it easier for health care providers to monitor the chronically ill and provide more personalized treatment to cancer patients.
The tiny, portable blood-testing laboratory measures about 14 mm long and is designed to be implanted just beneath the skin. The prototype has five sensors that allow it to detect up to five proteins and organic acids at once. The sensor surfaces are covered with an enzyme to capture targeted substances in the body, such as lactate, glucose, or Adenosine triphosphate (ATP). However, the enzymes being tested in the prototype are currently only good for about a month and a half.
"Potentially, we could detect just about anything," explains EPFL scientist Giovanni de Micheli. "But the enzymes have a limited lifespan, and we have to design them to last as long as possible." However, De Micheli points out that, “it's very easy to remove and replace the implant, since it's so small."
In addition to the sensors, the implant also packs a radio transmitter and a power delivery system into its few cubic millimeter volume. Instead of an inbuilt battery, the device has a tiny electrical coil that receives power inductively from a patch located outside the body that provides 1/10 watt of power through the patient’s skin.
The external patch also collects the data transmitted over a safe frequency from the implant and relays it via Bluetooth to a mobile phone or tablet, which then forwards the information to the doctor over the mobile network.
The research team, which was led by De Micheli and Sandro Carrara, believes the implant could be particularly useful to oncologists who use occasional blood tests to evaluate cancer patients’ tolerance to particular dosages of chemotherapy.
"It will allow direct and continuous monitoring based on a patient's individual tolerance, and not on age and weight charts or weekly blood tests,” De Michelli says.
In addition to potentially offering a more personalized form of chemotherapy, the implant could also be used in patients with chronic illness to identify a problem, such as an imminent heart attack or high blood sugar levels, and send an alert even before symptoms emerge.
The prototype has already been tested in the laboratory and proved to be as reliable as traditional analysis methods in detecting the five different substances it targeted. The researchers hope the implant will be commercially available within the next four years.
De Michelli and Carrera detail the implant and its potential uses in the following video.