Apple has hired a small team of biomedical engineers to work at a nondescript office in Palo Alto, California, miles from corporate headquarters.

They are part of a super secret initiative, initially envisioned by the late Apple co-founder Steve Jobs, to develop sensors that can noninvasively and continuously monitor blood sugar levels to better treat diabetes, according to three people familiar with the matter.

With Apple’s move into medical research over the last few years, this wouldn’t surprise me. They are more than just a technology, but this one is a tough nut to crack.