Chemistry and Physics of Lipids 94 (1998) 139–143 Short communication Liposome-DNA interaction: microcalorimetric study G.M. Mrevlishvili *, B.I. Kankia, T.J. Mdzinarashvili, T.I. Brelidze, M.M. Khvedelidze, N.O. Metreveli, G.Z. Razmadze Department of Physics, Tbilisi State Uniersity, Chachaadze a.1, 380028, Tbilisi, Georgia Received 10 March 1997; received in revised form 29 January 1998; accepted 16 March 1998 Abstract The authors applied differential scanning calorimetry (DSC) for studying the thermodynamic characteristics of DNA-liposome interactions. At the first stage, the melting curves of the ‘order – disorder’ thermal transition for lipid component and of the ‘ helix-coil’ transition for DNA were obtained. At the second stage, the phase behavior of the DNA-lipid mixture as a function of both components (lipid/DNA ratio) was obtained. The liposome-DNA interaction was investigated comparing the melting curves of the pure components and the mixture. © 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Liposomes; DNA; Phase transition; DSC 1. Introduction Differential scanning calorimetry (DSC) has been one of the most widely used methods for studying the thermal behavior of biological ob- jects including the thermotropic phases of pure lipids and isolated DNA in aqueous medium (Klump et al., 1990; Blume, 1991; Mrevlishvili et al., 1996). The authors have applied the DSC for studying the thermodynamic characteristics of DNA-liposome interaction. At present, this inter- action is insufficiently represented in scientific lit- erature. In (Kinnunen et al., 1993; Koiv et al., 1993, 1994) DSC data on the multilamellar lipo- somes and the influence of sphingozine and nu- cleic acids (DNA, RNA) upon the phospholipid liposomes thermal phase behavior was reported. From this paper the authors delivered informa- tion on interaction type between DNA and lipo- somes by recording the ‘order – disorder’ Abbreiations: DPC, 1,2-Ditetradecanoyl-sn-glycero-3-phos- phocholine; TDTMHA-Br, tetradecyltrimethylammonium bromide; DSC, differential scanning calorimetry. * Corresponding author. 0009-3084/98/$19.00 © 1998 Elsevier Science Ireland Ltd. All rights reserved. PII S0009-3084(98)00019-X