Mesoporous materials for dental and biotechnological applications, curcumin polymers and enzymatic saccharification of biomass
Authors:   , Mukherjee Indraneil , Wei Yen 
Published: July 2021

The nonsurfactant templated sol-gel route has been demonstrated to be a cost effective, green and biofriendly pathway to obtain mesoporous materials with an interconnected network ofwormhole-like pores. It involves the formation of a metal-oxide network around an inert organic molecule (e.g., sugar molecules) which functions as a template and can be later removed bysimple extraction with water or other solvents. This research describes the preparation of mesoporous zirconia and organo-functionalized silica by the acid-catalyzed nonsurfactant templated sol-gel route and also describes the use of sublimation as a method for the template removal. Mesoporous silica nanospheres with tunable particle size were also prepared by modifying the base-catalyzed Stober process with the addition of various sugar molecules as templates. The materials were characterized using TGA, nitrogen adsorption-desorption, SEM, TEM, XRD and FTIR. The application of nonsurfactant templated mesoporous materials in the area of enzyme encapsulation and stabilization is explored in this research. A novel 'double encapsulation'approach that enables a sol-gel encapsulated protease to retain 60 % of its original activity after 4 weeks in harsh environments, such as high pH buffer and laundry detergent, is demonstrated. The need for aesthetic, as well as durable, dental restorations has led to extensive research in the area of dental composites. This study examines the use of nonsurfactant templated mesoporous materials as fillers in dental composites. Mesoporous materials of irregular morphology prepared by acid-catalyzed sol-gel routes as well as mesoporous silica spheres prepared via base-catalyzed sol-gel reactions were both employed as fillers in experimental dental composites. This research led to the development of novel 'dental monomertemplated mesoporous materials', which were also evaluated as fillers in dental composites. Various approaches, such as dense packing, addition of nanosilica and spherical fillers, etc., were employed to fabricate nanocomposites with improved mechanical properties. The composites were evaluated using flexural and compression testing. Curcumin, the ground rhizome of Curcuma longa, a common South Asian herb has attracted much attention due to its chemopreventive and anti-inflammatory properties. This research describes the synthesis of a series of poly [(arylenedioxy)(diorganylsilylene)]s via polycondensation between curcumin and various diorganodichlorosilanes. These novel polymersincorporate the [beta]-diketone unit of curcumin as well as the Si-O bond in the backbone. The polymer structure was characterized by means of 1HNMR, FTIR and elemental analysis, whileGPC results showed high molecular weights. Preliminary cell culture results suggested lack of cytotoxicity, which is important for potential applications, such as implants and tissueengineering scaffold materials. The unique and interesting thermal behavior of these polymers was studied by DSC. The technology of enzymatically degrading biomass into simple sugars, such as glucose, is a critical step towards viable production of bio-based ethanol from non-food related sources. This research demonstrates the use of a biosensor-based diabetic blood glucose monitor as a rapid glucose detector and compares it to time consuming UV assays that are currently employed in research laboratories. Pretreatment of wood shavings with ferric chloride, followed by treatment in cold NaOH/urea solution was found to significantly enhance glucose production upon enzymatic hydrolysis. Finally, accounts of exploratory experiments in the areas of thermally crosslinkable high temperature elastomers and inorganic-organic hybrid materials are provided in the appendixsections of this thesis.