Effect of lipids and other substances on the adsorption of dipalmitoyl phosphatidylcholine.

The effect of various lipids, proteins, and other substances on the adsorption rate of dipalmitoyl phosphatidylcholine (DPC) was investigated. Each substance was added to a sonicated suspension of DPC in saline, and the surface pressure of the adsorbed surface film was measured using a platinum plate suspended from an electrobalance. Pure DPC adsorbed very slowly, being complete only after 8 hr; its half-adsorption time was 91.8 +/- 8.3 min. Four additives markedly reduced the half-adsorption time of DPC: dipalmitoyl phosphatidylglycerol (1.1 +/- 0.2 min), and surfactant apoprotein (0.9 +/- 0.1 min). The half adsorption times of mixtures of DPC and the other additives ranged from 15.3 +/- 1.9 to 107.8 +/- 12.1 min.