Photoinduced Processes in Supramolecular Assemblies made with DNA ?Bio-inspired? Polyelectrolytes

C.D: BORSARELLI

Santiago de Chile

Encuentro; 25th Inter-American Photochemical Society Meeting; 2016

Universidad Católica de Chile

Supramolecular assemblies of multifunctional biomimetic polyelectrolytes are of great interest in biophysical, bioanalytical, and biomedical fields. Polyelectrolytes develop these structures mainly by electrostatic interactions, such as with ionic dyes, and layer-by-layer (LbL) films between polyelectrolytes of opposite charge. Modification of polyelectrolyte chains with hydrophobic and/or reactive pendant groups can introduce new alternatives for the construction and properties of these supramolecular assemblies, e.g. size, shape, film thickness, mechanical stability, permeation, etc.We present recent studies regarding the preparation and characterization of hollow microcapsules (HMC) made of DNA-bioinspired polyelectrolytes containing vinylbenzylthymine (VBT) and vinylbenzyltriethylammonium chloride (VBA) or sodium vinylphenylsulfonate (VPS) monomers, to form polyelectrolytes of general structure {[(VBT)(VBA)m]m+}n or {[(VBT)(VPS)m]m-}n with m = 1, 2, 4 and 8 and n = 20-40. In this research, CaCO3 microspheres were used as sacrificial template removed with EDTA solutions. The effects of UV photolysis to produce direct photo-crosslinking of polyelectrolyte chains by dimerization of thymine pendant groups on the morphology and membrane permeability properties of the HMC were evaluated.The interaction of {[(VBT)(VBA)4]4+}n with Eosin Yellow (EY2-) xanthene dye was evaluated in aqueous solution and adsorbed onto quartz surfaces. The photo-physical and photo-sensitizing properties of the dye as function of the polyelectrolyte/dye molecular ratio were characterized, focusing on the generation of singlet molecular oxygen.The observed results reveal the suitability of the thymine-based polyelectrolytes for the design of micro/nano-devices with potential applications in controlled molecular release and photo-sensitized generation of reactive oxygen species.