No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / The degradation of the resin-dentin interface after restoration placement is multifactorial and can be attributed in part to matrix metalloproteinases (MMPs) enzymes associated with recurrent and secondary caries progression. This dissertation aimed to synthesize and characterize the effects of Epigallocatechin-3-gallate (EGCG) from green tea extract as an MMP-inhibitor loaded into a dental adhesive using slow therapeutic compound release nanotubes as a reservoir to allow sustained and slow release. Loading efficiency and drug release were evaluated using a UV-vis spectrometer. The effects on the degree of conversion (DC), polymerization conversion (PC), and Vickers Micro-Hardness (VHN) tests were performed. MMP mediated β-casein (bCN) cleavage rate was used to determine the potency of the eluates contained EGCG to inhibit MMP-9 activity. The results indicated that HNTs could hold about 21.35% (±4.2%) of the EGCG used in the encapsulation process. The addition of 7.5% HNT or 7.5% EGCG-encapsulated HNT adhesive groups did not alter the curing efficiency indicated by the degree of conversion, polymerization conversion, and surface hardness results compared to the control group (p> 0.05). A statistically significant influence of adding HNTs was found to slow down the EGCG release measured up to 8 weeks (p< 0.05). There was a significant decrease in the degradation of β-casein mediated by pre-activated MMP-9 exposed to eluates from EGCG adhesives compared to non-EGCG adhesive groups (p< 0.05). The results suggested that using HNTs for EGCG encapsulating can remedy the negative impact of EGCG on the adhesive’s polymerization and still have the MMP-inhibitory effect and longer release period. Dentin adhesive containing EGCG-encapsulated HNT may contribute to the long-term preservation of restorations through slow and controlled release to maintain the dentin-resin interface's integrity by inhibiting MMP activity.

Electronic applications have expanded to encompass a variety of materials. In particular, allotropes of carbon interest researchers for their electronic applications. Knowledge of carbon allotropes and their applications has expanded significantly since the discovery of C60 Buckminsterfullerene in 1985, the discovery of multi- and single-walled carbon nanotubes in the early 1990s, and the isolation of graphene in 2004. Single-walled carbon nanotubes (SWNTs) have the potential to bring next-generation electronic devices to fruition. Such devices could be flexible, conformable, and inexpensive. SWNT-based electronics are promising for chemical and biological sensing applications, for example, where high carrier mobilities are unnecessary, and material conformity and inexpensive processing are significant advantages. Considerable progress has been made in separating semiconducting SWNTs from metallic SWNTs, enabling SWNT incorporation into semiconducting electronic technologies. Selective sorting of semiconducting SWNTs using π-conjugated polymers is an effective and efficient technique to enrich large quantities of ultra-pure semiconducting SWNTs. Following semiconducting enrichment, SWNTs can be incorporated into electronic devices. This thesis focuses on the enrichment of semiconducting SWNTs via conjugated polymer extraction and incorporating the resulting polymer-SWNT dispersions into thin-film transistors (TFTs). Novel copolymers were investigated for their capacity to selectively sort and disperse large-diameter sc-SWNTs synthesized using the plasma torch technique. Absorption and Raman spectroscopy were employed to monitor the efficacy of the conjugated polymer extraction procedure. Following enrichment, the polymer-SWNT dispersions were incorporated into TFTs. The interaction between the conjugated polymer and the SWNT and the conjugated polymer and dielectric was an essential component of TFT optimization. Furthermore, the procedure of sorting and dispersing sc-SWNTs is investigated for its effect on TFT performance and was another component of TFT optimization. TFTs were electrically characterized in terms of carrier mobility, threshold voltage, hysteresis, and current on/off ratio. The film morphology of the SWNT TFTs was also investigated. Atomic force microscopy and Raman mapping were used to provide insight into the nanometre and micrometre scale film morphology, respectively.