Formation of Calcium Carbonate Crystal Using Phospholipid Monolayer Template Under Ambient Condition

Formation and assembly of monodispersed calcite (CaCO3) dots of diameters 6-10 nm using a zwitterionic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer as template at a two-dimensional interface is reported here. We utilized penetration of Ca2+ at lower surface pressure (pi) into the DPPC monolayer, governed by a single exponential association method. In situ surface pressure (pi)-area (A) isotherms as well as compressibility (beta) analysis reveal a positive association of Ca2+ with DPPC. The natural exposure of the resultant monolayer to air results in formation of single crystalline CaCO3 nanodots. HRTEM and SAED techniques have been used to study the crystal structure of the resultant CaCO3 nanodots incorporated within the lipid monolayer.