Application of atomic force microscopy to characterize liposomes as drug and gene carriers

At present, liposomes play a significant role as drug delivery vehicles being considered very promising for gene therapeutics. The in vivo application of these drug delivery systems widely depends on their physico-chemical and technological characteristics such as the structure, the shape, the size distribution, the surface modification and the drug interaction. To describe the liposomes, different analytical techniques were used. In this paper, we reviewed the application of the atomic force microscopy (AFM), one of the most commonly applied scanning probe microscopy (SPM) techniques, in the description of liposome. The advantages and limitations of these techniques are discussed comparing the reported data with those referred to other well-know microscopical and spectroscopical techniques such as transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). A detailed description of the application of AFM to evaluate the formation and the geometry of liposomes/DNA complexes is presented.