UCLA

The research covered in this dissertation is described in six chapters. The first two chapters focus on the design of supramolecular nanovalves on mesoporous silica and silicon materials to form drug delivery systems. These systems are capable of autonomously releasing drug molecules in vitro. The third chapter describes size-selective nanovalves that are able to control the release of both large and small molecules. These nanovalves are constructed on mesoporous silica materials with 6.5 nm pores. The fourth chapter demonstrates two experimental methods, dynamic fluorescence anisotropy and rigidochromism spectroscopy, for probing the properties of the microenvironment inside the mesopores of mesoporous silica nanoparticles. In the fifth chapter of this dissertation, the design and operation of a chemical amplifier based on enzyme-encapsulated mesoporous silica are shown. This system employs a pH-responsive nanogate assembly to control the access to the encapsulated enzyme. It is the first example of a chemical amplifier that is activated by and also amplifies the same type of reaction. The last chapter describes the spectroscopic consequences of the excited state mixed valence in a binuclear copper complex using a neighboring orbital model. The copper complex represents a new class of excited state mixed valence compounds, where the coupling of two equivalent charge-baring units is mediated through a copper-iodine cluster. The result from the simple neighboring orbital approach is supported by resonance Raman spectroscopy and Gaussian calculations.