ABSTRACT
This chapter summarizes physical and chemical methods used in the study of lung surfactants. Many of these methods are standard techniques from interfacial phenomena research modified as necessary to account for the special requirements of pulmonary surfactants. Standard methods noted in this chapter include organic chemical assays and purification methods, surface tension measurement methods, the Wilhelmy surface balance, and molecular biophysical methods (microscopic, spectroscopic, calorimetric) used to study surfactant films and multilayers. In addition, several techniques designed particularly for use with pulmonary surfactants, the pulsating bubble and captive bubble surfactometers, are described. These two instruments are highly useful in studying how adsorbed lung surfactant films lower surface tension during dynamic compression at physiologically relevant temperature, humidity, cycling rate, and area change. This information can then be used in conjunction with Wilhelmy balance and molecular biophysical studies, plus measurements of adsorption in the absence of diffusion and dynamic compression, to give a relatively complete picture of surface active behavior.
