Apple is building a team of senior medical technology executives, raising hackles in the biotechnology community and offering a hint of what the iPhone maker may be planning for its widely expected iWatch and other wearable technology. Over the past year, Apple has snapped up at least half a dozen prominent experts in biomedicine, according to LinkedIn profile changes. One prominent researcher moved two weeks ago, and Apple is recruiting other medical professionals and hardware experts, although the number of hires is not clear, said two people familiar with the hiring, who declined to be named. Much of the hiring is in sensor technology, an area Chief Executive Tim Cook singled out last year as primed “to explode.” Industry insiders say the moves telegraph a vision of monitoring everything from blood-sugar levels to nutrition, beyond the fitness-oriented devices now on the market.