"Chip" - what is it, definition of the term
An implantable microelectronic tag is a miniature, sealed semiconductor device placed subcutaneously in a rat or mouse to store a unique identification number that can be retrieved by radio‑frequency or near‑field scanning equipment, enabling precise tracking, data collection, and verification of individual animals in research, breeding, or pest‑management programs.
Detailed information
Micro‑electronic identifiers implanted in laboratory rodents provide permanent, unique codes that can be read without handling the animal. The device, typically a few millimetres long, contains an integrated circuit bonded to an antenna coil. When energized by a low‑frequency reader, the circuit transmits a numeric sequence stored in its memory.
The implantation procedure is performed under brief anaesthesia. A sterile trocar creates a subcutaneous pocket, usually between the scapulae, where the silicon implant is placed. The wound closes without sutures, allowing rapid recovery. Because the implant does not interfere with normal physiology, it can remain for the lifespan of the animal.
Key technical specifications include:
- Operating frequency: 125 kHz (low‑frequency) or 13.56 MHz (high‑frequency), selected according to the reader system.
- Memory capacity: 8–16 bytes, sufficient for a numeric identifier and optional data fields.
- Dimensions: length 2–5 mm, diameter 0.5–1 mm, weight <0.02 g.
- Materials: biocompatible polymer coating over a silicon die, resistant to tissue fluids and corrosion.
Advantages for rodent research are:
- Permanent, tamper‑proof identification eliminates the need for external tags that can be lost or chewed.
- Minimal impact on growth, behaviour, or breeding performance.
- Compatibility with automated tracking systems, enabling real‑time location data in behavioural experiments.
- Ability to store additional parameters, such as strain, birth date, or experimental group, which can be updated remotely.
Potential limitations involve the requirement for specialised readers and the need to ensure that the electromagnetic field does not interfere with other equipment. Calibration of the detection zone is essential to avoid missed reads, especially in densely populated cages.
Regulatory guidelines mandate that the implant be approved for animal use, that the procedure follows institutional animal care protocols, and that post‑operative monitoring confirms the absence of infection or adverse reactions. Documentation of the unique identifier in laboratory information management systems links each animal to its experimental records, enhancing data integrity and traceability.