X-ray diffraction (XRD) studies on the cationic liposomes (CL)-DNA complexes currently used in gene delivery have provided detailed structural informations on these compact, ordered self-assemblies sheding light on the poorly understood structure-activity relationship. Among these, the experiments carried out by using a synchrotron radiation source have showed an experimental resolution remarkably better than that achieved one by traditional in house apparatuses. Here we show a new experimental approach for the study of CL-DNA complexes, based on the employment of silicon wafers as substrates, which allows to obtain high-resolution structural informations by energy dispersive X-ray diffraction (EDXD). (C) 2002 Elsevier Science B.V. All rights reserved.