In 2015, the United States is expected to have nearly 600,000 deaths attributed to cancer. Of these 600,000 deaths, 90% will be a direct result of cancer metastasis, the spread of cancer throughout the body. During cancer metastasis, circulating tumor cells (CTCs) are shed from primary tumors and migrate through bodily fluids, establishing secondary cancer sites. As cancer metastasis is incredibly lethal, there is a growing emphasis on developing "liquid biopsies" that can screen peripheral blood, search for and identify CTCs. One popular method for capturing CTCs is the use of a detection platform with antibodies specifically suited to recognize and capture cancer cells. These antibodies are immobilized onto the platform and can then bind and capture cells of interest. However, current means to immobilize antibodies often leave them with drastically reduced function. The antibodies are left poorly suited for cell capture, resulting in low cell capture efficiencies. This body of work investigates the use of lipid-based fibers to immobilize proteins in a way that retains protein function, ultimately leading to increased cell capture efficiencies. The resulting increased efficiencies are thought to arise from the retained three-dimensional structure of the protein as well as having a complete coating of the material surface with antibodies that are capable of interacting with their antigens. It is possible to electrospin cholesterol-based fibers that are similar in design to the natural cell membrane, providing proteins a more natural setting during immobilization. Such fibers have been produced from cholesterol-based cholesteryl succinyl silane (CSS). These fibers have previously illustrated a keen aptitude for retaining protein function and increasing cell capture. Herein the work focuses on three key concepts. First, a model is developed to understand the immobilization mechanism used by electrospun CSS fibers. The antibody immobilization and cell capturing abilities of the CSS fibers were compared to that of hydrophobic polycaprolactone (PCL) fibers and hydrophilic plasma-treated PCL fibers. Electrospun CSS fibers were found to immobilize equivalent amounts of protein as hydrophobically immobilized proteins. However, these proteins captured 6 times more cells, indicative of retained protein function. The second key concept was the design and fabrication of a hybridized lipid fiber. Lipid fibers provide improved protein function but fabrication difficulties have limited their adoption. Thus, we sought to fabricate a lipid-polymer hybrid that is easily fabricated while maintaining protein function. The hybrid fiber consists of a PCL backbone with conjugated CSS. The hybrid lipid fibers showed improved protein function. In addition, higher lipid concentrations were directly correlated to higher cell capture efficiencies. The third key concept was on the development of dually functionalized lipid fibers and understanding the resulting cell capture efficiencies. Many platforms are unable to simultaneously search for heterogeneous populations of CTCs–the ability to dually functionalize cell-capturing platforms would address this technological weakness. Studies indicated that dually functionalizing the lipid fibers did not compromise the platforms' abilities to capture the cells of interest. Such dually functionalized fibers allow for a single cell-capture platform to successfully detect heterogeneous populations of CTCs. The body of work encompassed herein describes the use of lipid fibers for antibody immobilization and cell capture. Data from various projects indicate that the use of cholesterol-based fibers produced from electrospun CSS are well suited for protein immobilization. The CSS fibers are able to immobilize equivalent amounts of protein as compared to other immobilization techniques. However, the benefit of these fibers is illustrated by the strong cell-capturing efficiencies, indicating that the immobilized proteins are able to retain their function and selectively target cells of interest. The successful immobilization of proteins and their retained function allows for the development of increasingly sensitive cancer diagnostic tools that are able to screen for CTCs early on in the cancer disease cycle.

Over the past decades, there have been worldwide efforts to synthesize new types of ordered porous materials for catalysis, separations, etc. Among those, mesoporous material with microporous walls are promising in a sense that while mesopores act as channels for the reactant transport with little diffusion limitation, micropores in the wall act as active sites for reactions or storage of the molecules. In this study, we focused on the SBA-15 material, which is a highly ordered mesoporous silica material with micropores present in the wall. We have studied the synthesis of the material by manipulating various factors that are known to have influence on the porous characteristic of the material. We have aimed our studies particularly on the micropores present in the material. Unlike zeolite materials, which have regular, well characterized pore structures, micropores in the SBA-15 are not ordered, thus may have a very broad pore size distribution. We have synthesized sets of mesoporous silica materials that have characteristics similar to those reported in the literature. Using microwave heating, we were able to synthesize the target material within a short period of time, about 10 to 12-fold reduction of the conventionally known synthesis time. The synthesized materials were initially characterized using XRD and SEM. Adsorption studies were then undertaken on the materials to determine the surface area and pore structure. The interpretation of micropores has heretofore been problematic and the models are ambiguous. Relatively simply ordered, 1-dimensional channel type, zeolite materials were also studied; MTW, MTT, TON, ATS, VET frameworks. Adsorption isotherms of these materials were obtained and simple empirical models were developed to determine the pore size distribution. Further, a sequential adsorption technique, using n-nonane as a preadsorbate, was used to evaluate the realistic external surface areas of zeolite materials and mesopore surface areas of micro-mesoporous materials. Applying this technique to “multidimensional pore system” will provide another way to obtain the realistic surface area and mesopore size distribution.

The emerging contaminants (ECs) such as estrogen hormones, perfluorinated compounds (PFCs), bisphenol A (BPA) and 1, 4-dioxane have been detected in natural water bodies at a noticeable level worldwide. The presence of ECs in the aquatic environment can pose potential threats to aquatic organisms as well as human world. Ion-exchange is a highly efficient technology for the removal of heavy metal ions and natural organic materials (NOMs) due to the nature of exchanging similar charged ions. However, this technology has not been explored for removing ECs. In this study, four categories of ECs: estrogen hormones (12), perfluorinated compounds (10), bisphenol A and 1, 4-dioxane were used as model contaminants. The adsorption of each category of ECs onto various types of polymeric resins (MN100, MN200, A530E, A532E and C115) was investigated. The removal of ECs was tested under batch and column mode. The effects of pH, resin dosage, and contact time on the removal of ECs were studied in batch mode; isotherm and kinetics models were applied to fit the experimental data. Column experiments were conducted to verify the practicability of the polymeric resins. Adsorption results have shown that both MN100 and MN200 resins could efficiently remove estrogen hormones mixture (more than 95%), and bisphenol A (more than 80%) with the initial concentration of 100 ìg/L; A532E and A530E could remove perfuorinated compounds mixture (more than 99%) with the initial concentration of 100 ìg/L. As pH increased from 9 to 11, the adsorption capacity onto polymeric resins decreased dramatically for estrogen hormones such as 17á-ethinylestradiol, estriol, 17â-estradiol, 17á-estradiol, estrone, 17á-dihydroequilin and equilin as well as bisphenol A. The adsorption of estrogen hormones and bisphenol A onto MN100 and MN200 resins reached the equilibrium within 24 hours, whereas the adsorption of perfluorinated compounds onto A532E and A530E reached the equilibrium within 8 hours. It was also observed that the adsorption of PFCs largely depends on the C-C chain length. PFCs with longer chain yielded lower adsorption efficiency onto the ion-exchange resins A532E and A530E. Adding salinity decreased the first-order rate constants for the adsorption of bisphenol A onto MN100 and MN200 resins. Fixed-bed column experiment results with estrogen hormones mixtures confirmed that the polymeric resins were good candidates in the removal of estrogen hormones. Trimegestone was the first compound detected in the effluent in the column test while 17â-estradiol, 17á-estradiol were the last. 80% of the exhausted resins (MN100 and MN200) by bisphenol A were regenerated by using pure methanol as regeneration solution. Polymeric resins were not effectively removing 1, 4-dioxane from the aqueous solution. / Civil Engineering