טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentKlein Rinat
SubjectCharacterization of Pulmonary Surfactant with Throbbing
(Clicking) Bubble
DepartmentDepartment of Chemical Engineering
Supervisors Professor Emeritus Abraham Marmur
Mr. Zalman Weintraub


Abstract

Active lung surfactant plays an important role in the breathing process. Its deficiency leads to the respiratory distress syndrome (RDS) of premature infants, which is a substantial cause of infant mortality in the western world.

Qualitative and rapid tests (bed-side test) are essential for the immediate detection of lung surfactant deficiency in premature infants. The “bubble clicking” test has the best chances to become the most efficient bedside test, due to the small amount of material needed and the simple equipment required for the performance of the test.

The main objective of this work was to better understand the mechanism of the “bubble clicking” process, which is a complex and puzzling phenomenon. Reproduction of “clicks” under various experimental conditions, coupled with construction of a theoretical model, were vital for exploring the connection between size of the bubbles and the existence of the “clicks”.

A MATLAB-based program, which solves the Young-Laplace equation in its differential form, sets a basis for the development of the theoretical model. From this model, relationship between the clicking phenomenon and volume range of the bubbles was established. It was also demonstrated that the type of the surfactant (natural or artificial), the concentration of the surface-active component, and the surface energy of the solid have a substantial effect on the volume range of the “clicking” bubbles.

It was clearly shown by the model, that (1) there is a distinct region of volumes for which the same bubble could co-exist in two different shapes and surface tensions, and (2) clicking may occur only at very low surface tensions. Furthermore, the volume range of the clicking bubbles depends strongly on the surfactant concentration, surface energy and characteristic isotherm.