US EPA

5346175 

Journal Article 

Atomic force microscopy studies of Langmuir-Blodgett films. 3 Phase behavior of dipalmitoyl phosphatidyl choline monolayers 

Tomoaia-Cotisel, M; Tomoaia, G; Pop, VD; Mocanu, A; Cozar, O; Apetroaei, N; Popa, G 

2005 

1 

Revue Roumaine de Chimie
ISSN: 0035-3930 

50 

6 

471-478 

WOS:000233575500007 

Phase behavior and surface structure of dipalmitoyl phosphatidyl choline (DPPC) spread as Langmuir nanolayers at the air/water interface in the absence and, in the presence of two drugs in the aqueous phase, such as procaine (P) or deferoxamine (DFO), at a drug concentration of 10(-3) and 10(-6) mole dm(-3), respectively, have been investigated using Langmuir-Blodgett (LB) self-assembly technique and atomic force microscopy (AFM). The LB self-assembled films were transferred from nanolayers onto solid substrates, as glass optically polished, at different controlled surface pressures before collapse and at advanced collapse, using the vertical transfer and horizontal deposition method. In the presence of these drugs, the stability of DPPC films is highly increased as is seen from the high collapse pressures of mixed nanolayers at the air/water interface. Depending on the lateral surface pressure, highly ordered structures and less organized features have been directly evidenced. In addition these observations reveal some specific molecular interactions between these biologically relevant biocompounds in agreement with our thermodynamic studies. The different micro- and nano-structures evidenced by AFM measurements on LB mixed films of DPPC and P and of DPPC and DFO are in substantial agreement with the molecular structure of these biocompounds. The data indicate that both procaine and deferoxamine can penetrate and interact with membrane dipalmitoyl phosphatidyl choline stabilizing the membrane lipids at both internal and external membrane interfaces.