The word radiobiologists is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 22
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (39 words)
abiosis, adsorbs, astroid, batoids, biodots, bistros, bridals, bristol, dialogs, diarist, digital, dilator, disbars, disroot, distils, dogsits, dorsals, galoots, gliosis, idolist, isobars, libator, libidos, obligor, oboists, oilbird, oligist, orbital, ragbolt, sailors, soloist, sortals, tabloid, tabooli, tailors, toolbag, toolbar, toroids, tribals