LIPID-DNA FORMULATIONS: AN APPROACH TO BIODISTRIBUTION ASSAYS.

NADIA CHIARAMONI; LUCÍA SPERONI; MARÍA C. TAIRA; SILVIA DEL V. ALONSO-ROMANOWSKI

Buenos Aires, Argentina

Congreso; Reunion Anual de la Sociedad Argentina de Biofísica; 2003

LIPID-DNA FORMULATIONS: AN APPROACH TO BIODISTRIBUTION ASSAYS. Chiaramoni NS, Speroni L, Taira MC, and Alonso-Romanowski, S. Laboratorio de Biomembranas, UNQ. R. Saenz Peña 180. Bernal (1876) Buenos Aires. Argentina. E-mail: nschiara@unq.edu.ar Nowadays, stability determinations of lipid formulations require as mandatory the use of radioisotopes. This method is very expensive and toxic. To override this problem a cDNA fragment of VP7 inserted into pGEMT cloning-vector was selected as plasmid-DNA probe. VP7 is a protein of the outer envelope of the rotavirus capside. The objective is to develop a sensitive technique to study lipid bio-distribution. With this in mind, the viral dsRNA of the bovine rotavirus strain UK was extracted and a RT-PCR reaction was performed to obtain the cDNA corresponding to VP7. The plasmid DNA probe was encapsulated into several liposome formulations (Cationic, Non-Charged and Polymerized). The Lipid:DNA ratio was 300:1. Several assays were performed to characterize the formulations such us optical microscopy, electronic microscopy and spectrometry (osmotic volume determination). We observed that the non charged liposomes with DNA were half the size than the liposomes without DNA. The polymerized and cationic liposomes with DNA were bigger when compare to those without DNA. Finally, the cationic formulation had the highest efficiency of encapsulation, followed by the polymerized liposomes and the non-charged ones. Based on these studies we can use the selected formulations of liposomes as DNA carriers to study bio-distribution and in vivo stability.