Development and characterization of oligonucleotide-tagged dye-encapsulating EPC/DPPG liposomes

Liposomes applications in health care include meanly their ability to carry drugs and genes inside the human body for therapeutic purposes. Nevertheless their applicability can extend far beyond and could be used as analytical tools in order to perform rapid, low-cost, sensitive and specific analyses. Their physical characteristics, such as large internal volume and extended surface area, render them ideal for these applications and specifically for improving the specificity and sensitivity of the analytical assay. The purpose of this study was to develop a simple, stable and low-cost oligonucleotide-tagged liposomal formulation consisting of EggPC and DPPG with a simple to synthesize thiol-reactive conjugate (Mal-SA) incorporated into the lipid bilayer of liposomes. The prepared liposomes, having also the water soluble dye Sulforhodamine B encapsulated in their inner cavity, were characterized in terms of their physicochemical (size, size distribution, zeta-potential, lipid content) and mechanical (morphology, rigidity) properties. The results showed that the final liposomal formulation could be used in the future as analytical tool for detecting pathogen strains of microorganism in biological milieu.