Real-time imaging of interactions between dipalmitoylphosphatidylcholine monolayers and gelatin based nanoparticles using Brewster angle microscopy.

Given the current interest in the pulmonary route for targeted drug delivery, assessing the impact of drug delivery vehicles on the surfactant layer lining the surface of the lung alveoli is critical. As gelatin-based nanoparticles are one such vehicle, this study addresses their interaction with the major saturated phospholipid component of native lung surfactant, dipalmitoylphosphatidylcholine (DPPC). Nanoparticles are colloidal particles in the size range of 1 to 1000 nm that are presently investigated for site-specific drug delivery in the emerging field of nanomedicine. Monolayer studies of DPPC films were performed both in the presence and absence of nanoparticles in order to assess the interaction in terms of average molecular areas occupied at given surface pressures. In Brewster angle microscopy experiments, nanoparticles significantly changed the shape and reduced the size of DPPC domains suggesting a considerable interaction of the two systems. For safe pulmonary drug delivery, understanding this interaction is a prerequisite so nanoparticles can be a feasible alternative to more conventional therapies in the future.