Influence of Functional Groups on the Photodynamic Therapy and Internalization of Porphyrin Modified Polyhedral Oligomeric Silsesquioxane (POSS) Molecules in Mammalian Cells

Polyhedral Oligomeric Silsesquioxane (POSS) molecules are highly ordered organic- inorganic hybrid materials with a cage like core of alternating silicon and oxygen atoms surrounded by eight pedant organic residues. These compounds are well-defined, 3D building blocks that can form hybrid materials with precise control of the nanostructure and properties. POSS molecules are used in a wide variety of medical fields, for example, tissue engineering and drug delivery, or for the oligomerization of bioactive ligands, among them peptides and carbohydrates. They are considered non-toxic and hydrolytic degradation of the inorganic core under physiological conditions has been thoroughly investigated. In this work, we have taken advantage of the chemical and structural properties of POSS to functionalize this material with porphyrin. Moreover, the corner groups have been functionalized with either isobutyl or phenyl groups. We hypothesize that the differences in surface functionalization will have a major impact on the internalization and phototoxicity and of POSS-Porphyrin against mammalian cancer cells. Further studies will expand the scope of this investigation with drug-conjugated POSS molecules and target-specific systems.