Visual Vessels

In 1989 while our severely ill son lay in our arms my husband and I asked the surgeon what he would do if he were in our shoes. “Play the hand you’re dealt.” he replied. It was not this doctor’s only reference to the gamble life holds for each of us. Based on his advice to us I began to investigate the role that fate and predetermination play in our lives and consequently how much control we have on the outcome of life’s events. A cathartic family portrait piece laid the groundwork for a series of metaphorical portraits as I began to investigate identity. The continued use of identity as my thematic approach has allowed me to record emotional waypoints and personal change throughout my life and to additionally pose questions about what constitutes a portrait. At times this approach thankfully led me to use my art as a visual vessel, a container in which to place my emotional burdens lightening the load while I continued on in my daily lif

Ex Parte Communication in Informal Rulemaking: Judicial Intervention in Administrative Procedures

Over the past several years, a controversy has arisen, particularly among different panels of the United States Court of Appeals for the District of Columbia Circuit, regarding the use of ex parte communications in informal administrative rulemaking. Numerous theories for extending such a prohibition beyond the express language of the Administrative Procedures Act have been advanced in recent judicial opinions

Development of a Cellular Analysis Platform Featuring Arrays of Patterned Microwells Fabricated Atop Permeable Supports

Many human pulmonary diseases lead to accumulation of fluid in the alveoli, the air sacs located in the distal lung and at which gas exchange occurs. The most serious example of alveolar fluid buildup is in Acute Respiratory Distress Syndrome (ARDS), in which an insult to the lung results in injury to the cells lining the alveolus, leading to compromise of the alveolar capillary barrier and impaired gas exchange. Current ARDS mortality rates lie at 30-40%. Worsening this problem is the lack of disease-specific therapies for treating ARDS: the cornerstone of treatment is merely supportive respiratory care via mechanical ventilation. Further investigations into treating ARDS have been hampered by unresolved questions about the normal physiology of alveolar fluid transport. Therefore, new insights are needed in order to develop more effective ARDS therapies. The alveolus is lined by two types of cells: squamous alveolar type 1 cells that cover 98% of the alveolar surface area and small cuboidal alveolar type 2 cells. While studies have examined AT2 cells, the ion transport properties of AT1 cells remain unknown. Recent attempts to culture AT1 cells in bulk monolayers for ion and fluid transport studies have been unsuccessful. It was therefore hypothesized that a microscale device to grow single AT1 cells in conditions that mimic the native lung would enable study of AT1 ion transport. This dissertation describes the development of microfabricated devices that feature an array of microwells patterned atop a porous or otherwise permeable support. First, a method for fabricating 1002F photoresist into a freestanding microwell array is explored. Next, a strategy to co-fabricate freestanding 1002F films with the hydrogel chitosan to form microwells with a permeable support is described. Review of the literature suggests that this is the first reported co-fabrication of hydrogel and photoresist into a freestanding film. Lastly, an approach to micropattern commercially available permeable supports, etched with submicron-scale cylindrical pores, is presented. Together, these platforms offer potential for growth and analysis of not only primary alveolar cells, but a range of other cell types in a variety of research endeavors, pulmonary and otherwise.Doctor of Philosoph

Co-fabrication of chitosan and epoxy photoresist to form microwell arrays with permeable hydrogel bottoms

Microfabrication technology offers the potential to create biological platforms with customizable patterns and surface chemistries, allowing precise control over the biochemical microenvironment to which a cell or group of cells is exposed. However, most microfabricated platforms grow cells on impermeable surfaces. This report describes the co-fabrication of a micropatterned epoxy photoresist film with a chitosan film to create a freestanding array of permeable, hydrogel-bottomed microwells. These films possess optical properties ideal for microscopy applications, and the chitosan layers are semi-permeable with a molecular exclusion of 9.9 ± 2.1 kDa. By seeding cells into the microwells, overlaying inert mineral oil, and supplying media via the bottom surface, this hybrid film permits cells to be physically isolated from one another but maintained in culture for at least 4 days. Arrays co-fabricated using these materials reduce both large-molecular-weight biochemical crosstalk between cells and mixing of different clonal populations, and will enable high-throughput studies of cellular heterogeneity with increased ability to customize dynamic interrogations compared to materials in currently available technologies

Characterization of freestanding photoresist films for biological and MEMS applications

Photoresists are light-sensitive resins used in a variety of technological applications. In most applications, however, photoresists are generally used as sacrificial layers or a structural layer that remains on the fabrication substrate. Thin layers of patterned 1002F photoresist were fabricated and released to form a freestanding film. Films of thickness in the range of 4.5–250 μm were patterned with through-holes to a resolution of 5 μm and an aspect ratio of up to 6:1. Photoresist films could be reliably released from the substrate after a 12-hour immersion in water. The Young’s modulus of a 50 μm-thick film was 1.43 ± 0.20 GPa. Use of the films as stencils for patterning sputtered metal onto a surface was demonstrated. These 1002F stencils were used multiple times without deterioration in feature quality. Furthermore, the films provided biocompatible, transparent surfaces of low autofluorescence on which cells could be grown. Culture of cells on a film with an isolated small pore enabled a single cell to be accessed through the underlying channel and loaded with exogenous molecules independently of nearby cells. Thus 1002F photoresist was patterned into thin, flexible, free-standing films that will have numerous applications in the biological and MEMS fields

Characterization of freestanding photoresist films for biological and MEMS applications

Photoresists are light-sensitive resins used in a variety of technological applications. In most applications, however, photoresists are generally used as sacrificial layers or a structural layer that remains on the fabrication substrate. Thin layers of patterned 1002F photoresist were fabricated and released to form a freestanding film. Films of thickness in the range of 4.5–250 μm were patterned with through-holes to a resolution of 5 μm and an aspect ratio of up to 6:1. Photoresist films could be reliably released from the substrate after a 12-hour immersion in water. The Young’s modulus of a 50 μm-thick film was 1.43 ± 0.20 GPa. Use of the films as stencils for patterning sputtered metal onto a surface was demonstrated. These 1002F stencils were used multiple times without deterioration in feature quality. Furthermore, the films provided biocompatible, transparent surfaces of low autofluorescence on which cells could be grown. Culture of cells on a film with an isolated small pore enabled a single cell to be accessed through the underlying channel and loaded with exogenous molecules independently of nearby cells. Thus 1002F photoresist was patterned into thin, flexible, free-standing films that will have numerous applications in the biological and MEMS fields