When the Internet impresarios at Google speak, the world listens. So the usual hoopla ensued last month when Google announced its latest ambition: to develop nanoparticle diagnostics paired with a wearable detector. One interview even brought up the tricorder, the fictional diagnostic device from “Star Trek.”

Diagnostic development doesn’t happen at warp speed. Experts say Google hasn’t revealed enough information to know what if anything sets it apart from myriad competitors. Even if Google’s ideas survive the years-long development gauntlet, they add, the technology faces societal hurdles to adoption.

“Imagine you want to explore Parisian culture, and you do it by flying a helicopter over Paris once a year,” said Andrew Conrad, head of life sciences at the company’s semicovert Google X laboratories, while announcing the project at the Wall Street Journal’s WSJD Live conference on Oct. 28. “That’s what doctors do now” with annual screening, he said.

Google X envisions a way to mingle with Parisians, as it were: functionalized nanoparticles designed to bind to something specific, such as circulating tumor cells. Ideally, the nanoparticles would be swallowed in pill form and enter the bloodstream. The particles’ tiny cores could be made from magnetic iron oxide, a compound already in Food & Drug Administration-approved nanoparticle contrast agents. A wearable device that creates a magnetic field could summon the particles from outside the body, Conrad said. “We’d call them back to one place and we’d ask them, ‘Hey, what’d you see? Did you find cancer?’ ”