Identifier

etd-11112016-101845

Degree

Master of Science in Chemical Engineering (MSChE)

Department

Chemical Engineering

Document Type

Thesis

Abstract

Harmful algal blooms pose a threat to human health and the environment. Many complex factors influence their formation and development, and much is still unknown. One major influencing factor that is well-known yet poorly studied is algal chemotaxis. Many studies have examined chemotaxis in other organisms, but very little about chemotaxis in algae has been studied, largely because existing technology and assay techniques are inadequate. Microfluidics offers many possibilities for cell biology, and has been applied to the study of chemotaxis in other organisms already. These techniques can be applied to the study of algal chemotaxis as well. We present in this study a flow-free microfluidic gradient generator for the study of algal chemotaxis. The device consists of a bottom layer of agarose hydrogel and a top layer of PDMS imprinted with thee parallel microchannels. A gradient is formed by flowing media containing a chemoeffector in one of the outer channels and a buffer solution in the other, providing two constant-concentration boundary conditions. The center channel is left flow-free to allow cells to migrate freely in response to the gradient. We demonstrate the device operation using Chlamydomonas reinhardtii as our model organism, exposing the cells to a gradient of nitrogen in the form of ammonium. We also further demonstrate the device’s utility by modifying it for use in long-term culturing of algal cells, with the ultimate goal of studying allelopathy by culturing two species side-by-side. The modified device contains a second cell culture channel, enabling us to culture two different cell populations that are chemically connected via diffusion but kept physically separate. As a proof of concept, we successfully culture C. reinhardtii first in a 3-channel device, then in both channels of a 4-channel device.

Date

2016

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Melvin, Adam

DOI

10.31390/gradschool_theses.4496

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