AVS 63rd International Symposium & Exhibition
    Biomaterials Plenary Session Sunday Sessions
       Session BP-SuA

Invited Paper BP-SuA3
Formation of Stacked Lipid Lamellae and Development of Myelin-like Structures Is Promoted by a Surfactant Protein B Analog: A Micropipette Study of Lung Surfactants at Microscopic interfaces

Sunday, November 6, 2016, 3:40 pm, Room 101A

Session: Biomaterials Plenary
Presenter: David Needham, Duke University
Authors: D. Needham, Duke University
E. Parra, University Southern Denmark, Denmark
K. Konoshita, University Southern Denmark, Denmark
Correspondent: Click to Email
The present study is a microscopic interfacial characterization of a series of lung surfactant materials performed with the micropipette technique. We measured the equilibrium and dynamic surface tensions for a series of animal-derived and synthetic lung surfactant formulations, including a Super Mini-B (SMB)-containing formulation. Somewhat surprisingly interfacial structures were found to occur at these microscopic air-water interfaces (see Figure below) for the SMB-containing formulation over time and during area compression at the microscopic air-water interface. We compared the results to other lung surfactants, including: native surfactant obtained from porcine lungs (NS) and the commercial, animal-derived formulations Curosurf, Infasurf and Survanta. The presence of SMB promoted vesicle condensation as thick membrane multilayers beneath the interface, the nucleation and growth of microtubes emanating from these lamellae and their subsequent transformation into helices. The dimensions of these tubes (2-15 mm diameter) and their linear (2-3 mm/s) and volumetric growth rates (20-30 mm3/s) were quantified, and no specific effects were found on them for increasing SMB concentrations from 0.1 to 4%. Nevertheless, we found a direct correlation between the number of tubes and SMB contents, which suggests that SMB molecules are the promoters of tube nucleation in these membranes. Microtube formation was also observed in Infasurf, and in NS only after subsequent expansion and compression, but neither in the other clinical surfactants nor in protein-free preparations. The connection between this data and the observations from the lung surfactant literature concerning the widely reported “near-zero surface tension” for lung surfactant films and intact alveolar surfaces will also be discussed.