Human serum albumin–octadecylamine Langmuir–Blodgett film formed by spreading human serum albumin solution directly on subphase's interface covered with a layer of octadecylamine

Abstract

A new method of forming protein–lipid film by spreading human serum albumin (HSA) solution directly on the subphase's interface covered with a layer of octadecylamine (ODA) was studied, with HSA as model protein. The optimum equilibrium time of HSA interacting with ODA layer, the optimum amount of protein spread on subphase's interface, the optimum ionic strength and the pH of subphase were obtained according to the experimental results. The compressibility of the complex Langmuir–Blodgett (LB) film was used to character the phase transition during the compression process. The stability of the mixed film under different surface pressures was used to select suitable deposition conditions of HSA–ODA film from subphase's interface to gold electrode surface. The transfer efficiency of the complex film was estimated using quartz crystal microbalance technique. Because of less protein used and simple experimental process, this work offers an economical and convenient way to prepare protein–lipid LB film, especially for costly protein.