Date of Award

7-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Biological Sciences

Advisor

Ke, Pu-Chun

Committee Member

Mount , Andrew S

Committee Member

Klaine , Stephen J

Abstract

Dendrimers have found many applications in the fields of polymer science, biophysics, nanomedicine and the petroleum industry. Poly(amidoamine) (PAMAM) was studied as a model dendrimer and squalane as a model hydrocarbon. The interaction between PAMAM and squalane is pH dependent. Specifically, at low or neutral pH the squalane is found on the periphery of the PAMAM while at high pH the hydrocarbon is entrapped inside the PAMAM molecules.

Single-molecule fluorescence revealed that the interaction between PAMAM and squalane is reversible. At a pH value of 8, the time constants for the approaching, binding and dissociation of single PAMAM to squalane are 0.5s, 7.5s and 0.5s respectively. Spectrophotometric measurements revealed these interactions increase for dendrimers of lower generations.

PAMAM was found to be an effective vector for plant gene delivery. By optimizing the pH of the plant growth medium and the molar ratio of dendrimer to plasmid DNA, the expression of Green Fluorescent Protein (GFP) delivered by PAMAM is possible in turfgrass cells. In principle, this method could be extended to other plant cells by optimizing the dendrimer delivery system as necessary. Such novel scheme overcomes the pitfalls of conventional gene delivery means involving intensive labor, cost and host range limitations.

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