Chemical engineering of nanoshell chemical reactors
The objective of this project is to develop a reliable synthesis and characterization procedure for the development of silicate-based nanoshell chemical reactors. These materials may be useful in a wide range of areas including drug and gene delivery, biocatalysis, sensors, and photoactive devices. To achieve this objective, synthesis methods for two types of nanoparticle encapsulating a chemically or photochemically active species in aqueous and hydrophobic cores were evaluated. Templates used to form these shells included micelles, gold nanoparticles, and liposomes. Model compounds in the form of Cascade Blue dye, pyrene, and urease enzymes were encapsulated inside the nanoshells. The interdependence of shell formation and model compound encapsulation efficiency was characterized using a variety of colloidal and microscopic methods such as dynamic light scattering, transmission electron microscopy, atomic force microscopy, and steady-state and time resolved fluorescence. Using these methods, nanoparticle yields and size distributions, estimates of the internal viscosity, and diffusion of molecules in and out of the nanoshell as a function of chemical and physical environment were examined. Based on these results, the effect of nanoshell encapsulation on the kinetics of chemical reactions and their potential for future applications of these materials are evaluated.