G. R. IVANOV^1,* , G. AS. GEORGIEV², Z. I. LALCHEV²

Abstract

Organic monolayers from fluorescently labeled phospholipids, mainly DPPE-NBD, were deposited on solid supports under special conditions that form stable nanometer wide bilayer cylinders that protrude from the monolayer. This molecule was frequently used in sensor applications, due to its sensitivity to environmental changes. The proposed configuration should provide both fast response times (ultra thin films) and increased sensitivity (greatly increased surface area). Atomic Force Microscopy (AFM) can clearly distinguish between the different phases. The height difference between the solid-expanded and the liquid-expanded phases was measured to be 1.4 nm, while the bilayer thickness was 5.6 nm. The solid domains showed a 20 % decrease in the fluorescence lifetime in comparison to the monolayer, as measured by Fluorescence Lifetime Imaging Microscopy. This difference in lifetimes is explained in the model of fluorescence self quenching in the solid phase, due to the molecules being closer to each other..

Keywords

Langmuir-Blodgett films, phospholipids, Atomic Force Microscopy, fluorescence lifetime, Fluorescence Lifetime Imaging Microscopy, chemical sensors.

Submitted at: Nov. 5, 2008
Accepted at: Sept. 9, 2009

Citation

G. R. IVANOV, G. AS. GEORGIEV, Z. I. LALCHEV, Monolayers from fluorescently labelled phospholipids ♣, Journal of Optoelectronics and Advanced Materials Vol. 11, Iss. 9, pp. 1238-1240 (2009)

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