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 FeCl3. Adsorption and agglomeration of Fe3+ ions at DPPC head group have being monitored by Langmuir and Langmuir Blodgett (LB) technique. Adsorption kinetics (π–t) as well as the surface pressure area (π–A) isotherms measurement demonstrate the incorporation of Fe3+ ion at DPPC monolayer. The amount of incorporation of Fe3+ to the DPPC monolayer is FeCl3 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 Fe3O4 nanoparticle having size ∼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.