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A new challenge on the horizon is to utilize the large amounts of protein found in the atmosphere to identify different organisms from which the protein originated. Included here is work investigating the presence of identifiable patterns of different proteins collected from the air and biological samples for the purposes

A new challenge on the horizon is to utilize the large amounts of protein found in the atmosphere to identify different organisms from which the protein originated. Included here is work investigating the presence of identifiable patterns of different proteins collected from the air and biological samples for the purposes of remote identification. Protein patterns were generated using high performance liquid chromatography (HPLC). Patterns created could identify high-traffic and low-traffic indoor spaces. Samples were collected from the air using air pumps to draw air through a filter paper trapping particulates, including large amounts of shed protein matter. In complimentary research aerosolized biological samples were collected from various ecosystems throughout Ecuador to explore the relationship between environmental setting and aerosolized protein concentrations. In order to further enhance protein separation and produce more detailed patterns for the identification of individual organisms of interest; a novel separation device was constructed and characterized. The separation device incorporates a longitudinal gradient as well as insulating dielectrophoretic features within a single channel. This design allows for the production of stronger local field gradients along a global gradient allowing particles to enter, initially transported through the channel by electrophoresis and electroosmosis, and to be isolated according to their characteristic physical properties, including charge, polarizability, deformability, surface charge mobility, dielectric features, and local capacitance. Thus, different types of particles are simultaneously separated at different points along the channel distance given small variations of properties. The device has shown the ability to separate analytes over a large dynamic range of size, from 20 nm to 1 μm, roughly the size of proteins to the size of cells. In the study of different sized sulfate capped polystyrene particles were shown to be selectively captured as well as concentrating particles from 103 to 106 times. Qualitative capture and manipulation of β-amyloid fibrils were also shown. The results demonstrate the selective focusing ability of the technique; and it may form the foundation for a versatile tool for separating complex mixtures. Combined this work shows promise for future identification of individual organisms from aerosolized protein as well as for applications in biomedical research.
ContributorsStaton, Sarah J. R (Author) / Hayes, Mark A. (Committee member) / Anbar, Ariel D (Committee member) / Shock, Everett (Committee member) / Williams, Peter (Committee member) / Arizona State University (Publisher)
Created2011
Description

Dielectrophoresis is an analytical technique which involves electroosmotic flow, electrophoresis, and dielectrophoretic force. These factors, when in correct proportions for a given analyte, allow for dielectrophoretic trapping, otherwise known as dielectrophoretic capture. Non-uniform electric fields are required for this phenomenon, and the device in this trial used to induce such

Dielectrophoresis is an analytical technique which involves electroosmotic flow, electrophoresis, and dielectrophoretic force. These factors, when in correct proportions for a given analyte, allow for dielectrophoretic trapping, otherwise known as dielectrophoretic capture. Non-uniform electric fields are required for this phenomenon, and the device in this trial used to induce such an electric field was a gradient insulator-based design. Similar devices have been previously used to separate or identify a wide variety of analytes within solution. Much of the previous work has been focused on the differences in dielectrophoretic trapping between strains of bacteria, whereas this experiment focused on the differentiation of phenotypes within a single bacterial strain, Staphylococcus aureus isolate 35984. A control sample was tested, as well as a sample heated at 70oC for 15 minutes to induce phenotypic changes. The control sample was found to exhibit dielectrophoretic capture at a given gate at a potential of 800V and higher, whereas the heated sample was not observed to capture at any potential in this experiment, which reached a maximum of 1200V. Notably, neither of the samples were found to capture at or below 600V. The results of this experiment were encouraging, though it is worth noting that several experimental trials failed to produce any noteworthy results. As such, the procedure of this experiment should be refined to increase reproducibility of results.

ContributorsLehfeldt, Jase (Author) / Hayes, Mark (Thesis director) / Sayres, Scott (Committee member) / Williams, Peter (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor)
Created2023-05