A California-based company called Profusa has developed a biosensor smaller than a grain of rice that can measure levels of various substances in the body. The information is then passed along via an optical scanner held to the skin.

“They produce a continuous stream of data that gives us insight into the biochemical fluctuations that reflect our health,” said Natalie Wisniewski, Profusa’s co-founder and chief technical officer.

The technology gives promise to a brave new world of digital medicine. For instance:

• Diabetics can use it to receive instant and painless blood sugar readings, eliminating the need for needle sticks and making life easier for diabetics.

• Athletes will be able to monitor oxygen levels to optimize their workouts.

• In the arena of battlefield medicine, the biosensors could help medics determine which wounded military personnel to treat first.

And that’s just scratching the surface of the biosensors’ potential.