AEROSOLIZED FLUORESCENT MICROSPHERES DETECTED IN THE LUNG USING CONFOCAL SCANNING LASER MICROSCOPY

Aerosolized fluorescent microspheres were used to study particle depos ition in site-specific regions of the lung with confocal laser scannin g microscopy. A nebulizer was used to aerosolize microspheres followed by passage through a heated discharging column to reduce static charg e and to remove water surrounding each microsphere. Precoating of micr ospheres with albumin helped to minimize displacement during vascular fixation of the lungs. Confocal laser microscopy facilitated visualiza tion of microspheres throughout the bronchial tree, ducts, and alveoli of the lungs. The use of fluorescent microspheres and confocal laser imaging provided distinct advantages compared with other methods to st udy lung particle deposition due to (1) the generation of single micro spheres of uniform size by nebulization, (2) easy detection of microsp heres in large slabs of microdissected lung tissues, (3) excellent res olution of tissue surfaces and microspheres for an infinite number of orientations and planes of section, and (4) the ability to visualize m icrospheres below fluid lining layers and on surfaces that could not e asily be done by other methods of microscopy. (C) 1993 Wiley-Liss, Inc .