The wireless implant, developed by engineers at the University of California at Berkeley, measures the oxygen saturation of living tissue deep beneath the skin's surface.
The device, which is smaller than the average ladybug and powered by ultrasonic waves, will help doctors monitor the condition of the transplanted organs or tissues. Thus, it will provide early warning of potential problems after transplantation.
In addition, the technology paves the way for the creation of many miniature sensors. They will be able to track other key biochemical markers in the body, such as pH or carbon dioxide. They will one day provide physicians with minimally invasive methods for monitoring biochemistry within functioning organs and tissues.
Using ultrasound technology in combination with an integrated circuit can create complex implants that penetrate very deep into tissues to receive data from organs, the scientists note.
Most methods for measuring tissue oxygenation only provide information about what is happening at the surface of the body. They are based on electromagnetic waves that penetrate only a few centimeters under the skin or organ tissue. Although there are types of magnetic resonance imaging that provide information on deep tissue oxygen saturation, they are time consuming and do not provide real-time data.
The new sensor differs from pulse oximeters, which are used to assess blood oxygen saturation. While they measure the proportion of hemoglobin in the blood, the device directly measures the amount of oxygen in the tissues.
The implant is 4.5 cm long and 3 cm wide and consists of ΜLED, O2-sensitive film and an optical filter. The device itself is controlled by an integrated circuit (IC). The piezoelectric crystal converts the electronic signal from the IC into ultrasonic waves that are safely transmitted through living tissue.
One of the possible applications of the sensor is monitoring transplanted organs. The fact is that several months after transplantation, vascular complications may occur, which lead to graft dysfunction.