Black Film Method for assessment of foetal lung maturity

Black Film Method for Assessment of Foetal Lung Maturity 

The creation of sensitive methods for assessment of foetal lung maturity are needed for prophylactics and neonate treatment of RDS. Numerous methods for prediction of lung 

The microscopic foam bilayer proved to be an appropriate model for investigation of alveolar surface and alveolar stability as well [21]. This approach is in agreement with the findings of Scarpelli that at birth the lung surfactant takes the form of intraalveolar bubbles with formation of foam films [e.g. 2,22,23], 

The results on formation and stability of black foam films, on the first place those on bilayer foam films (NBF) (see Sections 3.4.1.2 and 3.4.4) have promoted the development of methods which enable lung maturity evaluation. The research on stability of amphiphile bilayers and probability for their observation in the grey foam films laid the grounds of the method for assessment of foetal lung maturity created by Exerowa et al. [20,24]. Cordova et al. [25] named it Exerowa Black Film Method. It involves formation of films from amniotic fluid to which 47% ethanol and 7-10 2 mol dm 3 NaCl are added [20,24]. In the presence of alcohol the surface tension of the solution is 29 mN m 1 and the adsorption of proteins from the amniotic fluid at the solution/air interface is suppressed, while that of phospholipids predominates. On introducing alcohol, the CMC increases [26], so that the phospholipids are present also as monomers in the solution. The electrolyte reduces the electrostatic disjoining pressure thus providing formation of black foam lipid films (see Sections 3.4.1.2 and 3.4.4). 

In order to apply the hole-nucleation theory of bilayer stability of Kashchiev-Exerowa [27] involving quantitative interpretation of the W(C) dependence (probability for observation of black films vs. surfactant concentration), the black films from amniotic fluid should be bilayer films. This is proved experimentally by two dependences Y hw) (Fig. 11.1) and hw(Cei) (Fig. 11.2). As it can be seen in Fig. 11.1, the equivalent film thickness is 8 nm and does not change with the increase in IT (which is the difference between the pressures in the 

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