Daunorubicin-silsesquioxane conjugates (POSS-DAU) for theranostic drug delivery system: Characterization, biocompatibility and drug release study

In this study, we describe the synthesis, physicochemical characterization and in vitro results of the evaluation of the biological behaviour of multifunctional nanoplatform based on inorganic polyhedral oligomeric silsesquioxane (POSS) grafted with antracycline antibiotics (daunorubicin, DAU) and/or short poly (ethylene glycol) chains (PEG). A high-efficient synthetic route is used to obtain soluble POSS-DAU and PEG-POSS-DAU conjugates. The POSS cage is activated by attachment of the anhydride rings and thus formed octakis-[3-(2-succinic anhydride)propyl, dimethylsiloxy]octasilsesquioxane (POSSAN) reacts with amino group of daunorubicin or methoxy-PEG. The chemical structure of conjugates is confirmed by 1H, 13C NMR and HRMS analyses. In vitro anticancer cytotoxic activity is compared for (i) full-substituted POSS (POSS-DAU8), (ii) partially substituted POSS (POSS-DAU3) and (iii) POSS with mixed substituents (mPEG4-POSS-DAU3) in HeLa cells using the MTT assay. The ability to intercalate into DNA strains is confirmed by gel electrophoresis method.