Functionalized nanoparticles as potential precursors for smart materials -

Abstract

Nucleobase functionalized magnetic nanoparticles, which combine the magnetic properties of iron oxide and the hydrogen bonding property of nucleobases, were investigated in this research. The magnetic property can be manipulated by external constant magnetic field to collect the nanoparticles and drive them through a medium for drug delivery, catalyst magnetic collection for recycling, heating treatment for hyperthermia, among other applications. While the hydrogen bonding property allows the nanoparticles to behave as crosslinkers. The magnetic nanoparticles were synthesized through two routes: the co-precipitation with hydrophilic surfaces and the thermal decomposition with hydrophobic surfaces. The surface functionalization was done by the “grafting to” and “grafting from” approaches. The anchoring groups that were investigated in the “grafting to” approach were catechol, hydroxamate, and silane. Whereas in the “grafting from” approach the Fe3O4 NPs were first functionalized by isocyanate group. The size of the Fe3O4 NPs was 35 nm for co-precipitation method and 8 nm for thermal decomposition method. Grafting densities increased from 7 uracil-nm2 using “grafting to” approach to 18 uracil-nm2 using “grafting from” approach. The success of the functionalization was confirmed by the proper analysis. These functionalized magnetic nanoparticles will be used in future works as crosslinkers to prepare smart hydrogels. In the second part of this thesis rhodamine B RhB loaded Poly Lactic-co-Glycolic Acid PLGA nanoparticles NPs were formulated by the single emulsion solvent evaporation method. The effect of the formulation parameters (PVA concentration, sonication time, and organic to aqueous volume ratio) on the size and encapsulation efficiency of the formulated PLGA NPs was studied. The optimized RhB loaded PLGA NPs had spherical morphology with 184 nm average diameter, 0.2 polydispersity index , -21 mV zeta potential, and 40percent encapsulation effi