title: Bidirectional surface analysis of monomolecular membrane harboring nanoscale reversible collapse structures.
abstract: Determination of orientation of nanoscale collapse structures formed within a Langmuir film at the air-aqueous interface has not been possible by existing experimental techniques. This is however of special importance for pulmonary surfactant films, which form reversible surface-associated reservoirs (SARs) under dynamic lateral compression and expansion. The direction of these SARs with respect to the interface has hitherto remained uncertain. We designed a methodological approach to investigate the directionality of SARs formed in a functional analogue of the pulmonary surfactant lining, where we transferred the compressed film on a holey substrate and performed bidirectional surface imaging of the hole spanning monomolecular membrane harboring SARs. This unambiguously showed association of SARs with the membrane toward the air-side, in contrast to the up to now commonly accepted view of an orientation toward the aqueous phase.
authors: Institute of Biochemistry, Westfälische Wilhelms Universität, Wilhelm-Klemm-Strasse2, 48149 Münster, Germany.
authors: Amit K
authors: AK
authors: Sachan
authors: Hans-Joachim
authors: HJ
authors: Galla