Dynamic surface tension of stable air-filled microbubbles prepared by freeze-drying a solution of lipid/surfactant mixture

We studied the equilibrium and dynamic adsorption properties of the suspension solutions prepared from a mixture of l-α-dipalmitoylphosphatidylcholine (DPPC), dicetyl phosphate (DCP), and Tyloxapol. Freeze-drying of suspension solutions significantly affects the dynamic behavior of DPPC, DCP, and Tyloxapol molecules at the air–water interface. Short time and long-time adsorption data obtained by maximum bubble pressure method show that Tyloxapol in a freeze-dried sample is preferentially adsorbed at the air–water interface, and a self-assembled structure in a freeze-dried sample (microbubble-rich) is much more stable than that of a non-freeze-dried sample (liposome-rich).