The VeriChip, a controversial radio-frequency identification chip (RFID), injected through a syringe, could be used as a sort of “human bar code” in security and medical applications.

Applied Digital Solutions initially plans to sell the chips in South America and Europe for use with pacemakers and defibrillators. Medical personnel could identify and monitor a patient’s implanted devices merely by running a handheld scanner over the patient’s chest. They expect FDA approval for U.S. sales later this year.

The VeriChip includes memory that holds 128 characters, an electromagnetic coil for transmitting data and a tuning capacitor, all encapsulated within a silicone-and-glass enclosure. The passive RF unit, which operates at 125 kHz, is activated by moving a company-designed scanner near the chip.

Applied Digital Solutions implanted its first human chips in September. A New Jersey surgeon, Richard Seelig, injected two of the chips into his arm and leg.

The company says the chips could have security tracking uses, implanted in young children, adults with Alzheimer’s disease, prisoners, and parolees.

Analysts said the chip might be too large for easy adoption and needed more memory and other features, such as global-positioning satellite receive capability and induction-based power-recharging techniques. GPS might help find lost children and adults, while larger memories would enable doctors to store vital patient information.