Effect of surface pressure on mixed dipalmitoyl-lecithin—serum albumin monolayer composition

1984; Elsevier BV; Volume: 10; Linguagem: Inglês

10.1016/0166-6622(84)80012-8

ISSN

1873-4340

Autores

Svetla G. Taneva, I. Panaı̈otov, Lisbeth Ter‐Minassian‐Saraga,

Tópico(s)

Inhalation and Respiratory Drug Delivery

Resumo

The lipoprotein surface film which covers the lung alveoli determines their stability and the observed lung pressure—volume hysteresis [1,2]. Serum albumin (SA) and dipalmitoyllecithin (DPL) mixed monolayers may serve as models for this alveolar surface film [3]. The change of surface pressure II of the mixed monolayers was measured during the cyclic alteration of the film area in the range 0–45 dyn cm−1 or 0–70 dyn cm−1. The initial monolayer composition changes, following the increase in surface pressure, as a result of three processes: Conformational changes of SA molecules and reversible expulsion of protein residues. Desorption (irreversible) of the biopolymer from the highly compressed mixed monolayers [7]. Collapse of dipalmitoyllecithin. Various approaches were used for the evaluation of compositional changes of mixed monolayers during monolayer compression. In the range of surface pressures between 13 and 45 dyn cm−1 processes (1) and (2) above involve the displacement of practically all SA residues from the surface plane. At II > 70 dyn cm−1 the monolayers were found to collapse irreversibly and DPL molecules were found to leave the surface. We conclude that the effect of surface pressure on mixed monolayer composition in the range of surface pressures 0–45 dyn cm−1 is due to processes (1) and (2). In the range 0–70 dyn cm−1, processes (1), (2) and (3) occur.

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