Laboratory animals penetrate telemetry barriers

A prototype of implantable telemetry for monitoring animals may allow for long-term studies without any restriction on positioning. The patented electronic device is unique as it is powered by a magnetic field.

The implantable telemetry technology is the result of a national-founded research project carried out at the Universitat Politècnica de Catalunya. It consists of a system for generating a uniform magnetic field as large as the application requires, allowing animals carrying the implants to move freely around their enclosures.

The equipment comprises one or more sensors for measuring physiological variables, a microcontroller, an RF transmitter, a parallel resonant tank circuit and a temporary energy storage module.

Juan Ramos, a scientist on the project, said, “It was conceived initially for monitoring animals inside the lab because we are using an inductive link to charge the batteries of the implant. If the capacity of the battery is increased (using new technology, larger size etc) the system can be used outside. The telemetry data is transmitted using an RF link in an ISM band.”

Ramos explained that previous implanted telemetry devices have used small batteries to provide power, but this has limited the lifespan of the device. The energy transfer was focused on a small area, which can cause restrictions on positioning and orientation. This invention differs by providing energy through the magnetic field to power the implant housed inside the animal. It is said the device can be used throughout the lifetime of the animal and does not interfere with its normal day-to-day activities and physiological behaviour.

For almost 25 years, telemetry technology has been used for drug research purposes and academic studies on animals. Tests have included muscle stimulation, behavioural observation, and monitoring blood pressure and other bodily functions.

Ramos believes more devices and uses of telemetry systems will be available in future; and by using the device, it may reduce the use of laboratory animals for research.

“The lifetime of our device is limited only by the reliability of the electronic components. We think, and it was one of our objectives, that fewer animals will be used with this technology. We can record and monitor the physiological variables of interest of the animals for long periods of time (years). Thus, it is possible to use, for example, the same animal in different experiments without changing the implant or sacrifice,” he said.

“During the analysis and design of the technology we kept in mind the international regulations of magnetic field exposure of animals and human beings. Moreover, we did some numerical analysis with thermal and electromagnetic simulation software to verify the theoretical analysis. The simulations were validated with in-vitro experiments.”

Currently the university is looking for companies to further develop the technology and to make it available on the market. It is available for licensing with technical cooperation.