A review of scanning probe microscopy investigations of liposomes-DNA complexes

Liposome-DNA complexes are one of the most promising systems for the protection and delivery of nucleic acids to combat neoplastic, viral, and genetic diseases. In addition, they are being used as models in the elucidation of many biological phenomena such as viral infection and transduction. In order to understand these phenomena and to realize the mechanism of nucleic acid transfer by liposome-DNA complexes, studies at the molecular level are required. To this end, scanning probe microscopy (SPM) is increasingly being used in the characterization of lipid layers, lipid aggregates, liposomes, and their complexes with nucleic acid molecules. The most attractive attributes of SPM are the potential to image samples with subnanometer spatial resolution under physiological conditions and provide information on their physical and mechanical properties. This review describes the application of scanning tunneling microscopy and atomic force microscopy, the two most commonly applied SPM techniques, in the characterisation of liposome-DNA complexes.