Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.

(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)

Complexation of polyelectrolytes

Joanna G Pool, University of Massachusetts Amherst

Abstract

Complexation found in nature was the inspiration and motivation to study three model systems to gain understanding into the underlying parameters that govern these events. Static and dynamic light scattering was predominately used to understand the complexation in three model systems: complexation of antimicrobial polymers with biomimetic vesicles, the complexation of protein to a semi-flexible polyelectrolyte and with a flexible polyelectrolyte. ^ Characterization of antimicrobial polymers in solution and their interactions with biomimetic vesicles were investigated in order to understand how antimicrobial polymers interacted with and killed bacteria. These studies observed that an aggregation of the vesicles correlated with antimicrobial activity. For these synthetic polymer systems, aggregation appeared to be a necessary component for antimicrobial activity,but was not indicative of activity. ^ Inspired by complexation found in nature between DNA and RNA and proteins model polyelectrolyte-protein systems were also investigated. The focus of this section was to understand how polymer flexibility, concentration, protein concentration, and ionic strength affected the phase behavior and presence of soluble aggregates in solution. Construction of phase diagrams for both semi-flexible and flexible polyelectrolye systems dsDNA and hyaluronic acid showed different phase diagrams,yet amazingly both systems showed a spontaneous selection of size of ∼230nm away from any phase boundary and was irrespective of salt concentration, polymer concentration, persistence length or protein concentration. ^ It was possible to gain insight into the internal packing of these two polyelectrolyte-protein complexes through static light scattering and fractal dimension analysis. Comparisons of the fractal dimension analysis of the DNA-lysozyme and HA-lysozyme was not affected by salt concentration and from analysis of the fractal dimension it was observed DNA-lysozyme aggregates, had a denser aggregate structure than the HA-lysozyme aggregate. It was also observed that away from the phase boundaries in each system the aggregate sizes and fractal dimensions were irrespective of polymer, salt, persistence length or protein concentration. ^

Subject Area

Polymer chemistry|Condensed matter physics|Biophysics

Recommended Citation

Pool, Joanna G, "Complexation of polyelectrolytes" (2008). Doctoral Dissertations Available from Proquest. AAI3325254.
http://scholarworks.umass.edu/dissertations/AAI3325254

Share

COinS