Scientists from University of California San Diego have developed a new ultra-low power implantable biosensor, called the BioMote. The sensor is a microelectrode electrochemical sensor intended to assess ethanol levels. The sensor is combined with a four-turn on-chip coil for radio frequency energy harvesting and communication.
According to lead researcher Professor Drew Hall, from UC San Diego Jacobs School of Engineering: “he ultimate goal of this work is to develop a routine, unobtrusive alcohol and drug monitoring device for patients in substance abuse treatment programs.” This overcomes the need for blood tests, which are invasive and time consuming, and breathalyzers, which are, to a degree, inaccurate.
The new chip, which measures just 0.85 by 1.2 millimetres, is of a sufficiently small size that it can be injected under the skin via a 16-gauge syringe. The sensor has the ability to perform continuous, long-term alcohol monitoring in relation to the person who has been fitted with the micro-sized device.
The BioMote sensor node is formed of three electrochemical sensors. The first is functionalized with an AOx enzyme, which is designed to measure ethanol. The second is an unfunctionalized sensor intended to measure background and non-specific chemicals. The third is a microelectrode equipped with a hydrogen ion selective membrane which performs pH measurements. Together the sensor permits a differential measure of the ethanol content in the subcutaneously fluid.
The complete sensor, as EE Europe News reports, works when alcohol oxidase interacts with ethanol, producing hydrogen peroxide as a by-product which is then oxidized to generate free electrons to be detected
In terms of energy demand, the entire chip draws just 970 nanowatts (one million times less power than a smartphone) and it is powered through a coupling between the on-chip coil and a wearable device at 985MHz. The ethanol data is transferred to a mobile device via a converter.
The research has been published in the research paper “A Sub-1 μW Multiparameter Injectable BioMote for Continuous Alcohol Monitoring”. The research were recently presented at the Custom Integrated Circuits Conference (CICC) in San Diego.
