On the origin of iron-oxide nanoparticle formation using phospholipid membrane template.

In this report, we have studied the formation of iron-oxide nanoparticle at biologically relevant phospholipids, DPPC Langmuir monolayer at air/water interface. Water subphase contains FeCl(3). Adsorption and agglomeration of Fe(3+) ions at DPPC head group have being monitored by Langmuir and Langmuir Blodgett (LB) technique. Adsorption kinetics (pi-t) as well as the surface pressure area (pi-A) isotherms measurement demonstrate the incorporation of Fe(3+) ion at DPPC monolayer. The amount of incorporation of Fe(3+) to the DPPC monolayer is FeCl(3) concentration and time dependent. This reaction kinetics is well fitted by single exponential association equation. The composite monolayers transferred to different substrates are characterized by UV-vis absorption spectroscopy and electron microscopy (FE-SEM and HR-TEM). Study shows the formation of monodisperse Fe(3)O(4) nanoparticle having size approximately 20 nm coated with DPPC mono or multilayer. The overall study indicates that the formation as well as assembly of iron-oxide nanoparticle in two dimensions is possible using lipid monolayer as a template. Copyright 2010 Elsevier B.V. All rights reserved.